Biggest changeYear Ended December 31, ( In thousands) 2023 2022 Net income (loss) $ 16,067 $ (59,574) Add (deduct): Interest income (31,091) (7,235) Provision for income taxes 1,710 938 Depreciation and amortization 7,095 4,870 Stock-based compensation expenses related to equity awards (1) 99,226 75,822 Public company costs (2) — 338 Acquisition transaction costs (3) — 185 Acquisition earn-out costs (4) 338 113 Gain on sale of capitalized software (5) (100) — Loss on disposal of leasehold improvements (6) 433 — Adjusted EBITDA $ 93,678 $ 15,457 ________________ (1) In addition to stock-based compensation expense of $95.2 million and $73.8 million for the years ended December 31, 2023 and 2022, this includes costs incurred related to taxes paid on equity transactions as follows: Year Ended December 31, (In thousands) 2023 2022 Research and development $ 1,693 $ 701 Sales and marketing 93 45 General and administrative 2,219 1,256 Total $ 4,005 $ 2,002 (2) Public company costs include costs associated with the establishment of our public company structure and processes, including consultant costs, a one-time fee associated with the set-up of our initial proxy statement, and fees paid to consultants and Deloitte for work in connection with remediation of the material weakness disclosed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021.
Biggest changeYear Ended December 31, ( In thousands) 2024 2023 Net income $ 88,574 $ 16,067 Add (deduct): Interest income (42,697) (31,091) Provision for income taxes 13,732 1,710 Depreciation and amortization 10,854 7,095 Stock-based compensation expenses related to equity awards (1) 120,267 99,226 Acquisition transaction costs (2) 774 — Acquisition earn-out costs (3) 200 338 Gain on sale of capitalized software (4) — (100) Loss on disposal of leasehold improvements (5) — 433 Impairment of capitalized software (6) 238 — Adjusted EBITDA $ 191,942 $ 93,678 ________________ (1) In addition to stock-based compensation expense of $110.5 million and $95.2 million for the years ended December 31, 2024 and 2023, respectively, this includes costs incurred related to taxes paid on equity transactions as follows: Year Ended December 31, (In thousands) 2024 2023 Research and development $ 2,318 $ 1,693 Sales and marketing 130 93 General and administrative 7,342 2,219 Total $ 9,790 $ 4,005 (2) Represents costs incurred related to acquisitions, including integration costs, which are included in General and administration expense within our Consolidated Statements of Operations and Comprehensive Income (Loss).
We invest heavily in research and development to create new products and product features that help us grow our base, engage our users, monetize our users, and teach our users. This, in turn, drives additional growth in, and better lifetime value of, our paid subscribers, as well as increased advertising revenue from impressions from our free users.
We invest heavily in research and development to create new products and product features that help us grow our user base, engage our users, monetize our users, and teach our users. This, in turn, drives additional growth in, and better lifetime value of, our paid subscribers, as well as increased advertising revenue from impressions from our free users.
We grew DAUs through many of the same product initiatives as we grew MAUs, such as making the product more fun and engaging. Paid Subscribers. Paid subscribers are defined as users who pay for access to any Duolingo subscription offering and had an active subscription as of the end of the measurement period.
We grew DAUs through many of the same marketing and product initiatives as we grew MAUs, such as making the product more fun and engaging. Paid Subscribers. Paid subscribers are defined as users who pay for access to any Duolingo subscription offering and had an active subscription as of the end of the measurement period.
Interest Income Interest income consists of income earned on our money market funds included in cash and cash equivalents and on our marketable securities. Other (expense) income, net Other (expense) income, net consists primarily of foreign currency exchange gains and losses.
Interest Income Interest income consists of income earned on our money market funds included in cash and cash equivalents and income earned and net accretion on our marketable securities. Other (expense) income, net Other (expense) income, net consists primarily of foreign currency exchange gains and losses.
The following table sets forth the components of our Consolidated Statements of Operations and Comprehensive Income (Loss) for each of the periods presented as a percentage of revenue.
The following table sets forth the components of our Consolidated Statements of Operations and Comprehensive Income for each of the periods presented as a percentage of revenue.
For more information, refer to Note 7, Leases, in the notes to our Consolidated Financial Statements included in Part II, Item 8 of this Annual Report on Form 10-K. (3) Other business purchase commitments consist of hosting costs and web services.
For more information, refer to Note 7, Leases, in the notes to our Consolidated Financial Statements included in Part II, Item 8 of this Annual Report on Form 10-K. (3) Other business purchase commitments consist of hosting costs, web services and generative AI costs.
Non-GAAP Financial Measures We use certain non-GAAP financial measures to supplement our Consolidated Financial Statements, which are presented in accordance with GAAP. These non-GAAP financial measures include Adjusted EBITDA and free cash flow. We use these non-GAAP financial measures for financial and operational decision-making and as a means to evaluate period-to-period comparisons.
Non-GAAP Financial Measures We use certain non-GAAP financial measures to supplement our Consolidated Financial Statements, which are presented in accordance with GAAP. These non-GAAP financial measures include Adjusted EBITDA, free cash flow and constant currency. We use these non-GAAP financial measures for financial and operational decision-making and as a means to evaluate period-to-period comparisons.
The measurement period for MAUs is the three months ended December 31, 2023 and the same period in the prior year where applicable, and the analysis of results is based on those periods. MAUs are a measure of the size of our global active user community on Duolingo.
The measurement period for MAUs is the three months ended December 31, 2024 and the same period in the prior year where applicable, and the analysis of results is based on those periods. MAUs are a measure of the size of our global active user community on Duolingo.
The measurement period for DAUs is the three months ended December 31, 2023 and the same period in the prior year where applicable, and the analysis of results is based on those periods. DAUs are a measure of the consistent engagement of our global user community on Duolingo.
The measurement period for DAUs is the three months ended December 31, 2024 and the same period in the prior year where applicable, and the analysis of results is based on those periods. DAUs are a measure of the consistent engagement of our global user community on Duolingo.
Provision for income taxes 71 Table of Contents The provision for income taxes represents the income tax provision associated with our operations based on the tax laws of the jurisdictions in which we operate. In addition to the U.S., we also operate in foreign jurisdictions that have different statutory rates.
Provision for income taxes 69 Table of Contents The provision for income taxes represents the income tax provision associated with our operations based on the tax laws of the jurisdictions in which we operate. In addition to the U.S., we also operate in foreign jurisdictions that have different statutory rates.
Other Revenue For users who are unable or unwilling to pay a subscription fee, we provide free access to our product and generate advertising revenue from the sale of display and video advertising delivered through 64 Table of Contents advertising impressions. We generally enter into arrangements with the major programmatic advertising networks to monetize our advertising inventory.
Other Revenue For users who are unable or unwilling to pay a subscription fee, we provide free access to our product and generate advertising revenue from the sale of display and video advertising delivered through advertising impressions. We generally enter into arrangements with the major programmatic advertising networks to monetize our advertising inventory.
As of December 31, 2023, subscribers made up 8.3% of our average MAUs over the last twelve months as compared to 7.8% of our average MAUs during the year ended December 31, 2022. Subscription Our subscription offerings as of the date of this filing are called Super Duolingo and Duolingo Max.
As of December 31, 2024, subscribers made up 8.8% of our average MAUs over the last twelve months as compared to 8.3% of our average MAUs during the year ended December 31, 2023. Subscription Our subscription offerings as of the date of this filing are called Super Duolingo and Duolingo Max.
Management evaluates its accounting 77 Table of Contents policies, estimates and judgments on an ongoing basis. Management bases its estimates and judgments on historical experience, current trends and various other factors that are believed to be relevant at the time the Consolidated Financial Statements are prepared. Actual results may differ from these estimates under different assumptions and conditions.
Management evaluates its accounting policies, estimates and judgments on an ongoing basis. Management bases its estimates and judgments on historical experience, current trends and various other factors that are believed to be relevant at the time the Consolidated Financial Statements are prepared. Actual results may differ from these estimates under different assumptions and conditions.
Components of Our Results of Operations Revenue We generate revenues primarily from the sale of subscriptions. The term-length of our subscription agreements are primarily monthly or annual, with the family plan offered as an annual subscription. We also generate revenue from advertising, the in-app sale of virtual goods, and the Duolingo English Test.
Components of Our Results of Operations Revenue We generate revenues primarily from the sale of subscriptions. The term-length of our subscription agreements are primarily monthly or annual, with the family plan offered as an annual subscription. We also generate revenue from advertising, the in-app sale of virtual goods, and the Duolingo English Test, as well as from Duo’s Taquería.
Increased engagement and efficacy, we believe, help drive organic growth in MAUs and DAUs, 74 Table of Contents growth in, and better retention of, paid subscribers, as well as increased advertising opportunities with free users. Sales and Marketing.
Increased engagement and efficacy, we believe, help drive organic growth in MAUs and DAUs, growth in, and better retention of, paid subscribers, as well as increased advertising opportunities with free users. Sales and Marketing.
Overview Our flagship app has organically become the world’s most popular way to learn languages and the top-grossing Education app in the App Stores, offering courses in over 40 languages to over 85 million monthly active users for the three months ended December 31, 2023.
Overview Our flagship app has organically become the world’s most popular way to learn languages and the top-grossing Education app in the App Stores, offering courses in over 40 languages to over 100 million monthly active users for the three months ended December 31, 2024.
The following table presents a reconciliation of our net income (loss), the most directly comparable financial measure presented in accordance with GAAP, to Adjusted EBITDA.
The following 65 Table of Contents table presents a reconciliation of our net income, the most directly comparable financial measure presented in accordance with GAAP, to Adjusted EBITDA.
General and administrative expenses also include certain professional services fees, general corporate and director and officer insurance, our facilities costs, public company costs to comply with the rules and regulations of the SEC and the Listing Rules of the Nasdaq Global Select Market, and other general overhead costs that support our operations.
General and administrative expenses also include certain professional services fees, general corporate and director and officer insurance, our facilities costs, public company costs to comply with the rules and regulations of the Securities and Exchange Commission (“SEC”) and the Listing Rules of the Nasdaq Global Select Market, and other general overhead costs that support our operations.
For a discussion of changes from the year ended December 31, 2022 to the year ended December 31, 2021, refer to Management’s Discussion and Analysis of Financial Condition and Results of Operation in Part II, Item 7. of our Annual report on Form 10-K for the year ended December 31, 2022 (filed with the SEC on March 1, 2023).
For a discussion of changes from the year ended December 31, 2023 to the year ended December 31, 2022, refer to Management’s Discussion and Analysis of Financial Condition and Results of Operation in Part II, Item 7. of our Annual Report on Form 10-K for the year ended December 31, 2023 (filed with the SEC on February 29, 2024).
In-app purchases consist of learners purchasing one-time benefits within the app, such as “Streak Freezes” and “Timer Boosts.” In addition to monetizing the Duolingo App, we generate revenue from the Duolingo English Test by charging test takers a one-time fee that generally costs $59. University program acceptance is a driver of Duolingo English Test revenue.
We also offer in-app purchases, which consist of learners purchasing one-time benefits within the app, such as “Streak Freezes” and “Timer Boosts.” In addition to monetizing the Duolingo App, we generate revenue from the Duolingo English Test by charging test takers a one-time fee. University program acceptance is a driver of Duolingo English Test revenue.
As of December 31, 2023, we had deferred revenues of $249.2 million, which is recorded as a current liability and expected to be recognized as revenue in the next 12 months, provided all other revenue recognition criteria have been met.
As of December 31, 2024, we had deferred revenues of $372.9 million, which is recorded as a current liability and expected to be recognized as revenue in the next 12 months, provided all other revenue recognition criteria have been met.
Recent Accounting Pronouncements 81 Table of Contents See Note 1. Description of the Business and Basis of Presentation and Note 2. Summary of Significant Accounting Policies in the notes to our Consolidated Financial Statements included in Part II, Item 8 of this Annual Report on Form 10-K for a discussion of Recent Accounting Pronouncements.
Recent Accounting Pronouncements 77 Table of Contents See Note 1, “Description of the Business and Basis of Presentation,” and Note 2, “Summary of Significant Accounting Policies,” in the notes to our Consolidated Financial Statements included in Part II, Item 8 of this Annual Report on Form 10-K for a discussion of recent accounting pronouncements.
(4) Represents costs incurred related to the earn-out payment on an acquisition, which is included within General and administrative within our Consolidated Statements of Operations and Comprehensive Income (Loss). (5) Represents proceeds from a sale of capitalized software, which is included within Other (expense) income, net within our Consolidated Statements of Operations and Comprehensive Income (Loss).
(3) Represents costs incurred related to the earn-out payments on acquisitions, which is included within General and administrative expense within our Consolidated Statements of Operations and Comprehensive Income (Loss). (4) Represents proceeds from a sale of capitalized software, which is included within Other (expense) income, net within our Consolidated Statements of Operations and Comprehensive Income (Loss).
As of December 31, 2023, we maintained a valuation allowance of approximately $156,870 against our domestic net deferred tax assets primarily related to net operating loss carryforwards, research and development credit carryforwards and research and development expense capitalization.
As of December 31, 2024, we maintained a valuation allowance of approximately $256,728 against our domestic net deferred tax assets primarily related to net operating loss carryforwards, research and development credit carryforwards and research and development expense capitalization.
(2) Consists of future non-cancelable minimum rental payments under an operating lease obligation, committed to in December 2023, and commencing in January 2024. These payments are not reflected on our balance sheet as of December 31, 2023.
(2) Consists of future non-cancelable minimum rental payments under an operating lease obligation, committed to in March 2024, and commencing in the first half of 2025. These payments are not reflected on our balance sheet as of December 31, 2024.
Historically, the number of users on our platform and the number of subscribers we have increase in the beginning of the year and then moderate throughout the first quarter and second quarter back to our secular growth trend.
Historically, the number of users on our platform and the number of subscribers we have increase in the beginning of the year and then moderate throughout the first quarter and second quarter.
We measure the fair value of our options on the date of grant using the Black-Scholes pricing model which requires the use of several estimates, including the volatility of our share price, the expected life of the option, risk free interest rates and expected dividend yield.
We generally grant our option awards in a combination of service-based and performance-based. We measure the fair value of our options on the date of grant using the Black-Scholes pricing model which requires the use of several estimates, including the volatility of our share price, the expected life of the option, risk free interest rates and expected dividend yield.
We had approximately 88.4 million and 60.7 million MAUs for the three months ended December 31, 2023 and 2022, respectively, representing an increase of 46% from the prior year period.
We had approximately 116.7 million and 88.4 million MAUs for the three months ended December 31, 2024 and 2023, respectively, representing an increase of 32% from the prior year period.
We regularly test product improvements with our users. Many of these tests start by making small changes in the product that affect small numbers of users. As the tests evolve, they can require increasing investment and can impact more users.
Many of these tests start by making small changes in the product that affect small numbers of users. As the tests evolve, they can require increasing investment and can impact more users.
This has allowed us to scale to more than 85 million MAUs for the three months ended December 31, 2023.
This has allowed us to scale to more than 100 million MAUs for the three months ended December 31, 2024.
Provision for income taxes Provision for income taxes increased $0.8 million, during the year ended December 31, 2023, primarily attributable to the impact, for U,S, federal and state income tax purposes, of the capitalization of research and development expenses in accordance with Internal Revenue Code ("IRC") Section 174.
Provision for income taxes Provision for income taxes increased by $12.0 million to $13.7 million during the year ended December 31, 2024, from $1.7 million during the year ended December 31, 2023 primarily attributable to the impact, for U.S. federal and state income tax purposes, of the capitalization of research and development expenses in accordance with Internal Revenue Code Section 174.
We had approximately 26.9 million and 16.3 million DAUs for the three months ended December 31, 2023 and 2022, respectively, representing an increase of 65% from the prior year period. The DAU / MAU ratio, which we believe is an indicator of user engagement, increased to 30.4% from 26.9% a year ago.
We had approximately 40.5 million and 26.9 million DAUs for the three months ended December 31, 2024 and 2023, respectively, representing an increase of 51% from the prior year period. The DAU / MAU ratio, which we believe is an indicator of user engagement, increased to 34.7% from 30.4% a year ago.
Adjusted EBITDA is defined as net income (loss) excluding interest income, income taxes, depreciation and amortization, stock-based compensation expenses related to equity awards, IPO 67 Table of Contents and public company costs, transaction costs related to an acquisition, acquisition earn-out costs, gain on sale of capitalized software and loss on disposal of leasehold improvements.
Adjusted EBITDA is defined as net income excluding interest income, income taxes, depreciation and amortization, stock-based compensation expenses related to equity awards, transaction costs related to acquisitions, acquisition earn-out costs, gain on sale of capitalized software, loss on disposal of leasehold improvements and impairment of capitalized software.
We use non-GAAP constant currency revenues and non- 69 Table of Contents GAAP percentage change in constant currency revenues for financial and operational decision-making and as a means to evaluate period-to-period comparisons.
We use non-GAAP constant currency measures and non-GAAP percentage change in constant currency measures for financial and operational decision-making and as a means to evaluate period-to-period comparisons.
Our future capital requirements will depend on many factors, including our subscription growth rate and renewal activity, the timing of cash received from our payment processing platforms, the expansion of our sales and marketing activities, the introduction of new products and the enhancements to existing products, and the current uncertainty in the global markets.
Our future capital requirements will depend on many factors, including our subscription growth rate and renewal activity, the timing of cash received from our payment processing platforms, the expansion and efficacy of our sales and marketing activities, the introduction of new products and the enhancements to existing products, and the current uncertainty in the global markets impacting, for example, consumer spending, inflation and foreign currency exchange rates.
This increase was mainly due to: • Increased direct marketing and other expenses of $5.8 million, and • Increased personnel costs of $3.0 million driven primarily by the growth in headcount, including increased stock-based compensation expense of $1.4 million.
This increase was mainly due to: • Increased direct marketing and other expenses of $11.2 million; and • Increased personnel costs of $3.5 million driven primarily by the growth in headcount, including increased stock-based compensation expense of $1.0 million. 72 Table of Contents General and Administrative.
If we cannot meet our future capital requirements, we may be required to seek additional equity. If we are unable to raise additional capital or generate cash flows necessary to expand our operations and invest in continued innovation, we may not be able to compete successfully, which would harm our business and financial condition and results of operations.
If we are unable to raise additional capital or generate cash flows necessary to expand our operations and invest in 73 Table of Contents continued innovation, we may not be able to compete successfully, which would harm our business and financial condition and results of operations.
Super Duolingo offers learners additional features to enhance their learning experience. Duolingo Max, which is available to a portion of our user base, gives learners access to the existing features of Super Duolingo in addition to incremental features and exercises powered by generative AI technology.
Super Duolingo offers learners additional features to enhance their learning experience. Duolingo Max gives learners access to the existing features of Super Duolingo in addition to incremental features and exercises powered by generative AI technology.
Operating Expenses Our operating expenses consist of research and development, sales and marketing, and general and administrative expenses. Personnel costs are the most significant component of operating expenses and 70 Table of Contents consist of salaries, benefits, and stock-based compensation expense. Operating expenses also include overhead costs for facilities, including depreciation expense. Research and Development.
Personnel costs are the most significant component of operating expenses and consist of salaries, benefits, and stock-based compensation expense. Operating expenses also include overhead costs for facilities, including depreciation expense. Research and Development.
The measures set forth below should be considered in addition to, not as a substitute for or in isolation from, our financial results prepared in accordance with GAAP.
The measures set forth below should be considered in addition to, not as a substitute for or in isolation from, our financial results prepared in accordance with generally accepted accounting principles in the U.S. (“GAAP”).
Total revenues were $531.1 million for the year ended December 31, 2023, which represents an increase of 44% (on both a reported and constant currency basis) over the year ended December 31, 2022.
Total revenues were $748.0 million for the year ended December 31, 2024, which represents an increase of 41%, on both a reported and constant currency basis, over the year ended December 31, 2023.
Subscription revenues totaled $404.7 million for the year ended December 31, 2023, which represented an increase of 48% (on both a reported and constant currency basis) over the year ended December 31, 2022. Seasonality We experience some seasonality in both user growth and monetization on our platform.
Subscription bookings totaled $730.7 million for the year ended December 31, 2024, which represents an increase of 47% on a reported basis and 49% on a constant currency basis, over the year ended December 31, 2023. Seasonality We experience some seasonality in both user growth and monetization on our platform.
Free cash flow represents net cash provided by operating activities, reduced by capitalized software development costs and purchases of property and equipment and increased by taxes paid related to stock-based compensation equity awards, IPO and public company costs, transaction costs related to an acquisition and an acquisition earn-out payment as we believe they are not indicative of future liquidity.
Free Cash Flow . Free cash flow is defined as net cash provided by operating activities, reduced by capitalized software development costs and purchases of property and equipment and increased by taxes paid related to stock-based compensation equity awards, transaction costs related to acquisitions and acquisition earn-out payments as we believe such items are not indicative of future liquidity.
The following table summarizes our cash flows for the periods presented: Year Ended December 31, (In thousands) 2023 2022 Net cash provided by operating activities $ 153,614 $ 53,656 Net cash used for investing activities (13,584) (14,174) Net cash provided by financing activities 2,135 14,776 Net increase in cash, cash equivalents and restricted cash $ 142,165 $ 54,258 Operating Activities Cash flows from operating activities can fluctuate significantly from period to period due to timing of payments and cash collections.
The following table summarizes our cash flows for the periods presented: Year Ended December 31, (In thousands) 2024 2023 Net cash provided by operating activities $ 285,513 $ 153,614 Net cash used for investing activities (217,330) (13,584) Net cash (used for) provided by financing activities (30,002) 2,135 Net increase in cash, cash equivalents and restricted cash $ 38,181 $ 142,165 Operating Activities Cash flows from operating activities can fluctuate significantly from period to period due to timing of payments and cash collections.
Research and development continues to be our largest operating expense as we invest in it to create new products and product features and improve existing ones to drive engagement and efficacy of our products.
Research and development continues to be our largest operating expense as we test and experiment with new products and product features and improve existing ones to drive engagement and efficacy.
Year Ended December 31, 2023 2022 Revenues 100 % 100 % Cost of revenues 27 27 Gross profit 73 73 Operating expenses: Research and development 37 41 Sales and marketing 14 18 General and administrative 25 32 Total operating expenses 76 91 Loss from operations (2) (18) Other (expense) income, net — — Loss before interest income and income taxes (3) (18) Interest income 6 2 Income (loss) before income taxes 3 (16) Provision for income taxes — — Net income (loss) and comprehensive income (loss) 3 % (16) % Revenues Revenues increased $161.6 million, or 44%, to $531.1 million during the year ended December 31, 2023, from revenues of $369.5 million during the year ended December 31, 2022.
Year Ended December 31, 2024 2023 Revenues 100 % 100 % Cost of revenues 27 27 Gross profit 73 73 Operating expenses: Research and development 31 37 Sales and marketing 12 14 General and administrative 21 25 Total operating expenses 64 76 Income (loss) from operations 8 (2) Other (expense) income, net — — Income (loss) before interest income and income taxes 8 (3) Interest income 6 6 Income before income taxes 14 3 Provision for income taxes 2 — Net income and comprehensive income 12 % 3 % Revenues Revenues increased by $216.9 million, or 41%, to $748.0 million during the year ended December 31, 2024, from revenues of $531.1 million during the year ended December 31, 2023.
The following table provides the change in cost of revenues, along with related gross margins: Year Ended December 31, 2023 2022 Change % Change (In thousands, except gross margin) Costs Gross Margin Costs Gross Margin Costs Gross Margin Total cost of revenues $ 142,105 73.2 % $ 99,431 73.1 % $ 42,674 0.1 % Operating Expenses Research and Development.
The following table provides the change in cost of revenues, along with related gross margins: Year Ended December 31, 2024 2023 Change (In thousands, except gross margin) Costs Gross Margin Costs Gross Margin Costs Gross Margin Total cost of revenues $ 203,645 72.8 % $ 142,105 73.2 % $ 61,540 (0.4)% Operating Expenses Research and Development.
We use non-GAAP percentage change in constant currency revenues, which exclude the impact of fluctuations in foreign currency exchange rates, for financial and operational decision-making and as a means to evaluate period-to-period comparisons. We believe this information is useful to investors to facilitate comparisons and better identify trends in our business.
The effect of currency exchange rates on our business is an important factor in understanding period to period comparisons. We use non-GAAP percentage change in constant currency revenues and bookings, which exclude the impact of fluctuations in foreign currency exchange rates, for financial and operational decision-making and as a means to evaluate period-to-period comparisons.
Our generation of net income as compared to a net loss in the comparative period was due to a combination of our growth in revenue, a reduction in operating expenses as a percentage of revenue as compared to the prior year period, and an increase in interest income of $23.9 million during the year ended December 31, 2023.
The increase in net income as compared to the comparative period was due to a combination of our growth in revenue and interest income in addition to a reduction in operating expenses as a percentage of revenue as compared to the prior year period.
For the years ended December 31, 2023 and 2022, we generated Adjusted EBITDA of $93.7 million and $15.5 million, respectively. Adjusted EBITDA increased due to a combination of our growth in revenue and a reduction in operating expenses as a percentage of revenue as compared to the prior year periods. Free Cash Flow.
For the years ended December 31, 2024 and 2023, we generated Adjusted EBITDA of $191.9 million and $93.7 million, respectively, representing an increase of $98.3 million. Adjusted EBITDA increased due to a 66 Table of Contents combination of our growth in revenue and a reduction in operating expenses as a percentage of revenue as compared to the prior year periods.
Sales and marketing expense increased by $8.8 million, or 13%, to $75.8 million during the year ended December 31, 2023 from $67.0 million during the year ended December 31, 2022.
Sales and marketing expense increased by $14.7 million, or 19%, to $90.5 million during the year ended December 31, 2024 from $75.8 million during the year ended December 31, 2023.
Sales and marketing expenses are expensed as incurred and consists primarily of brand advertising, marketing, digital and social media spend, field marketing, travel, trade show sponsorships and events, conferences, and employee-related compensation, including stock-based compensation for personnel engaged in sales and marketing functions, and amortization of non-revenue generating capitalized software used to promote Duolingo.
Sales and marketing expenses are expensed as incurred and consists primarily of new user acquisition, brand marketing, digital and social media content, and employee-related compensation, including stock-based compensation, for personnel engaged in sales and marketing functions, amortization of non-revenue generating capitalized software used to promote Duolingo and depreciation of certain property and equipment. General and Administrative.
Three Months Ended December 31, (Operating metrics are in millions) 2023 2022 Operating Metrics Monthly active users (MAUs) 88.4 60.7 Daily active users (DAUs) 26.9 16.3 Paid subscribers (at period end) 6.6 4.2 65 Table of Contents Year Ended December 31, (In thousands) 2023 2022 Operating Metrics Subscription bookings $ 495,497 $ 331,803 Total bookings $ 622,181 $ 428,647 Non-GAAP Financial Measures Net income (loss) (GAAP) $ 16,067 $ (59,574) Adjusted EBITDA $ 93,678 $ 15,457 Net cash provided by operating activities (GAAP) $ 153,614 $ 53,656 Free cash flow $ 144,273 $ 46,170 Operating Metrics Monthly active users (MAUs).
Three Months Ended December 31, (In millions) 2024 2023 Operating Metrics Monthly active users (MAUs) 116.7 88.4 Daily active users (DAUs) 40.5 26.9 Paid subscribers (at period end) 9.5 6.6 Year Ended December 31, (In thousands) 2024 2023 Operating Metrics Subscription bookings $ 730,737 $ 495,497 Total bookings $ 870,601 $ 622,181 Non-GAAP Financial Measures Net income (GAAP) $ 88,574 $ 16,067 Adjusted EBITDA $ 191,942 $ 93,678 Net cash provided by operating activities (GAAP) $ 285,513 $ 153,614 Free cash flow $ 274,937 $ 144,273 63 Table of Contents Operating Metrics Monthly active users (MAUs).
If the stock-price hurdles are met sooner than the requisite service period, the stock-based compensation expense will be adjusted to prospectively recognize the remaining expense over the remaining derived service period. Provided that the founders continue to provide services to us, stock-based compensation expense is recognized over the derived service period, regardless of whether the stock-price hurdles are achieved.
If the stock-price hurdles are met sooner than the requisite service period, the stock-based compensation expense will be adjusted to prospectively recognize the remaining expense over the remaining derived service period.
Research and development expense increased by $43.9 million, or 29%, to $194.4 million during the year ended December 31, 2023 from $150.4 million during the year ended December 31, 2022. The increase was mainly due to: • Increased net personnel costs of $40.0 million.
Research and development expense increased by $40.9 million, or 21%, to $235.3 million during the year ended December 31, 2024 from $194.4 million during the year ended December 31, 2023. The increase was mainly due to: • Increased net personnel costs of $39.5 million, driven primarily by the growth in headcount.
The impact of changes in foreign currency may vary significantly from period to period, and such changes generally are outside of the control of our management. We calculate constant currency revenues by using current period foreign currency revenues and translating them to constant currency using prior year comparable period exchange rates for the entire period of related bookings.
We calculate constant currency revenues by using current period foreign currency revenues and translating them to constant currency using prior year comparable period exchange rates for the entire period of related bookings. We calculate constant currency bookings by using current period foreign currency bookings and translating them to constant currency using prior year comparable period exchange rates.
Our cash and cash equivalents primarily consist of bank deposits and money market funds. Our marketable securities consist of U.S. government treasury and agency securities. We believe that our existing cash and cash equivalents, and cash flow from operations will be sufficient to support working capital and capital expenditure requirements for at least the next 12 months.
Our short-term investments consist mainly of corporate debt securities, U.S. Treasury securities, certificates of deposit, and commercial paper. We believe that our existing cash and cash equivalents, short-term investments and cash flow from operations will be sufficient to support working capital and capital expenditure requirements for at least the next 12 months.
By excluding certain items that may not be indicative of our recurring core operating results, we believe that Adjusted EBITDA and free cash flow provide meaningful supplemental information regarding our performance.
By excluding certain items that may not be indicative of our recurring core operating results, we believe that Adjusted EBITDA, free cash flow and constant currency provide meaningful supplemental information regarding our performance. The effect of currency exchange rates on our business is an important factor in understanding period to period comparisons.
Stock-based Compensation ASC 718 requires all stock-based payments to employees, including grants of employee stock options, to be recognized in the income statement based on their fair values. We generally grant our option awards in a combination of service-based and performance-based.
Equity Based Compensation We follow ASC 718, Compensation-Stock Compensation , to account for our equity based compensation. 75 Table of Contents Stock-based Compensation ASC 718 requires all stock-based payments to employees, including grants of employee stock options, to be recognized in the income statement based on their fair values.
We typically capitalize a small portion of research and development costs, mostly consisting of wages, each year into capitalized software when the work is specific to launching a new product, or making major upgrades to our existing products or platforms. We expect engineers, designers, and product managers to represent a significant portion of our employees for the foreseeable future.
We typically capitalize a small portion of research and development costs once the product has reached application development phase, mostly consisting of wages, each period into capitalized software when the work is specific to launching a new product, or making major upgrades to our existing products or platforms. We regularly test product improvements with our users.
General and administrative expense increased by $14.3 million, or 12%, to $132.1 million during the year ended December 31, 2023 from $117.8 million during the year ended December 31, 2022.
General and administrative expense increased by $23.9 million, or 18%, to $156.0 million during the year ended December 31, 2024 from $132.1 million during the year ended December 31, 2023.
Cash provided by operating activities increased by $100.0 million, or 186%, to $153.6 million for the year ended December 31, 2023 from $53.7 million for the year ended December 31, 2022.
Cash provided by operating activities increased by $131.9 million, or 86%, to $285.5 million for the year ended December 31, 2024 from $153.6 million for the year ended December 31, 2023.
We expect our sales and marketing expenses will decline as a percentage of revenues over the long-term. General and Administrative. General and administrative expenses primarily consist of employee-related compensation, including stock-based compensation, for management and administrative functions, including our finance and accounting, legal, and people teams.
General and administrative expenses primarily consist of employee-related compensation, including stock-based compensation, for management and administrative functions, including our finance and accounting, legal, and people teams.
See Note 9, “Stock Based Compensation,” to our Consolidated Financial Statements appearing elsewhere in Annual Report on Form 10-K, for further information on equity based compensation. Restricted Stock Units (RSUs) We began to grant RSUs in November 2020. The fair value of RSUs is estimated based on the fair value of our common stock on the date of grant.
See Note 10, “Stock-Based Compensation,” to our Consolidated Financial Statements in the notes to our Consolidated Financial Statements included in Part II, Item 8 of this Annual Report on Form 10-K for a discussion of equity based compensation. Restricted Stock Units (RSUs) We began to grant RSUs in November 2020.
The main drivers of this increase were due to the following: • Increased personnel costs of $3.9 million, including increased stock-based compensation expense of $2.2 million; • Increased web services and technology costs of $2.7 million; • Increased travel and meals expenses of $2.3 million; • Increased professional fees of $2.7 million; and • Net increases in other costs of $3.5 million were due to increases in facility-related costs, sales and VAT taxes and charitable contributions.
This increase was mainly due to: • Increased net personnel costs of $11.6 million, including an increase of $4.4 million in stock-based compensation related expense; • Increased travel and meals expenses of $3.2 million; • Increased facility-related costs of $2.8 million; • Increased web services and technology costs of $2.8 million; • Increased professional fees of $1.9 million; and • Increased other expenses of $2.4 million.
Results of Operations Comparison of the years ended December 31, 2023 and 2022 The following table sets forth our Consolidated Statements of Operations and Comprehensive Income (Loss) data, including year-over-year change, for the periods indicated: Year Ended December 31, (In thousands) 2023 2022 % Change Revenues $ 531,109 $ 369,495 44% Cost of revenues (1) (2) 142,105 99,431 43 Gross profit 389,004 270,064 44 Operating expenses: Research and development (1) (2) 194,352 150,444 29 Sales and marketing (1) (2) 75,788 66,967 13 General and administrative (1) (2) 132,123 117,848 12 Total operating expenses 402,263 335,259 20 Loss from operations (13,259) (65,195) (80) Other (expense) income, net (55) (676) (92) Loss before interest income and income taxes (13,314) (65,871) (80) Interest income 31,091 7,235 >100 Income (loss) before income taxes 17,777 (58,636) nm Provision for income taxes 1,710 938 nm Net income (loss) and comprehensive income (loss) $ 16,067 $ (59,574) nm ________________ (1) Includes stock-based compensation expenses as follows: Year Ended December 31, (In thousands) 2023 2022 Cost of revenues $ 55 $ 38 Research and development 45,119 26,373 Sales and marketing 3,908 2,540 General and administrative 46,139 44,869 Total $ 95,221 $ 73,820 72 Table of Contents (2) Includes amortization of capitalized software and depreciation of property and equipment as follows: Year Ended December 31, (In thousands) 2023 2022 Cost of revenues (a) $ 2,020 $ 870 Research and development 1,650 1,500 Sales and marketing (a) 1,165 1,072 General and administrative 2,260 1,428 Total $ 7,095 $ 4,870 ________________ (a) Amortization of capitalized software is recorded to Cost of revenue and Sales and marketing for revenue and non-revenue generating capitalized software, respectively.
Results of Operations Comparison of the years ended December 31, 2024 and 2023 The following table sets forth our Consolidated Statements of Operations and Comprehensive Income data, including year-over-year change, for the periods indicated: Year Ended December 31, (In thousands) 2024 2023 % Change Revenues $ 748,024 $ 531,109 41 Cost of revenues (1) (2) 203,645 142,105 43 Gross profit 544,379 389,004 40 Operating expenses: Research and development (1) (2) 235,298 194,352 21 Sales and marketing (1) (2) 90,494 75,788 19 General and administrative (1) (2) 155,992 132,123 18 Total operating expenses 481,784 402,263 20 Income (loss) from operations 62,595 (13,259) nm Other (expense) income, net (2,986) (55) >100 Income (loss) before interest income and income taxes 59,609 (13,314) nm Interest income 42,697 31,091 37 Income before income taxes 102,306 17,777 >100 Provision for income taxes 13,732 1,710 >100 Net income and comprehensive income $ 88,574 $ 16,067 >100 ________________ (1) Includes stock-based compensation expenses as follows: Year Ended December 31, (In thousands) 2024 2023 Cost of revenues $ 68 $ 55 Research and development 60,076 45,119 Sales and marketing 4,912 3,908 General and administrative 45,421 46,139 Total $ 110,477 $ 95,221 70 Table of Contents (2) Includes amortization of capitalized software and depreciation of property and equipment as follows: Year Ended December 31, (In thousands) 2024 2023 Cost of revenues (a) $ 5,310 $ 2,020 Research and development 2,358 1,650 Sales and marketing (a) 860 1,165 General and administrative 2,326 2,260 Total $ 10,854 $ 7,095 ________________ (a) Amortization of capitalized software is recorded to Cost of revenue and Sales and marketing for revenue and non-revenue generating capitalized software, respectively.
Total gross personnel costs, including capitalized wages and $19.7 million of increased stock-based compensation expense, increased by $46.7 million, which was partially offset by a $6.7 million increase in wages capitalized into capitalized software compared to the prior year; • Increased web services and technology costs of $4.7 million; and • Increased travel and meal costs of $1.5 million; The above increases were partially offset by a decrease in contractor costs of $2.0 million and other costs of $0.3 million.
Additionally, there was an increase of $1.6 million due to a reduction in wages recorded as capitalized software as compared to the prior year; • Increased web services and technology costs of $3.3 million; and • Increased travel and other costs of $2.0 million. The above increases were partially offset by a decrease in net contractor costs of $3.9 million.
Gross Profit and Gross Margin Gross profit represents revenues less cost of revenues. Gross margin is gross profit expressed as a percentage of revenues. Our gross profit may fluctuate from period to period as our revenues fluctuate, and also as a result of the timing and amount of investments we make in items related to cost of revenues.
Our gross profit may fluctuate from period to period as our revenues fluctuate, and also as a result of the timing and amount of investments we make in items related to cost of revenues. 68 Table of Contents Operating Expenses Our operating expenses consist of research and development, sales and marketing, and general and administrative expenses.
We believe bookings provide an indication of trends in our operating results, including cash flows, that are not necessarily reflected in our revenues because we recognize subscription revenues ratably over the lifetime of a subscription, which is generally from one to twelve months.
We believe bookings provide an indication of trends in our operating results, including cash flows, that are not necessarily reflected in our revenues because we recognize subscription revenues ratably over the lifetime of a subscription, which is generally from one to twelve months. 64 Table of Contents For the years ended December 31, 2024 and 2023, we generated $730.7 million and $495.5 million of subscription bookings, respectively, representing an increase of $235.2 million, or 47% from the prior year period.
Other companies, including companies in our industry, may calculate these non-GAAP financial measures differently or not at all, which reduces their usefulness as comparative measures. The effect of currency exchange rates on our business is an important factor in understanding period to period comparisons.
Other companies, including companies in our industry, may calculate these non-GAAP financial measures differently or not at all, which reduces their usefulness as comparative measures. Adjusted EBITDA.
The main drivers of the increase were: • Subscription revenue increased by $131.2 million during the year ended December 31, 2023, primarily due to an increase in the average number of paid subscribers during the period; • Advertising revenue increased by $5.1 million during the year ended December 31, 2023.
The main drivers of the increase were: • Subscription revenue increased by $202.8 million, or 50%, to $607.5 million during the year ended December 31, 2024, primarily due to an increase in the average number of paid subscribers during the period; • Other revenue increased by $14.1 million, or 11%, to $140.5 million during the year ended December 31, 2024, driven by increased advertising revenue of $5.0 million and In-App Purchases of $4.0 million, both of which were primarily driven by the increase in DAUs.
For the years ended December 31, 2023 and 2022, we generated $495.5 million and $331.8 million of subscription bookings, respectively, representing an increase of 49% from the prior year period. We grew subscription bookings by selling more first-time and renewal subscriptions.
We grew subscription bookings by selling more first-time and renewal subscriptions. For the years ended December 31, 2024 and 2023, we generated $870.6 million and $622.2 million total bookings, respectively, representing an increase of $248.4 million, or 40% from the prior year period. We grew total bookings primarily through growth in subscription bookings as noted above.
Expenses are primarily made up of costs incurred for the development of new and improved products and features in our applications. Such expenses include employee-related compensation, including stock-based compensation, of engineers, designers, and product managers, in addition to materials, travel and direct costs associated with the design and required testing of our platform.
Such expenses include employee-related compensation, including stock-based compensation, of engineers, designers, and product managers, in addition to materials, travel and direct costs associated with the design, required testing of our platform and depreciation of certain property and equipment. We expect engineers, designers, and product managers to represent a significant portion of our employees for the foreseeable future.
The above increases were partially offset by decreases in insurance costs of $0.9 million. Interest Income Interest income increased by $23.9 million during the year ended December 31, 2023, due to an increase in interest rates earned on our money market funds and higher average balances.
The above increases were partially offset by decreases in insurance and other costs of $0.8 million. Interest Income Interest income increased by $11.6 million, or 37%, to $42.7 million during the year ended December 31, 2024, from $31.1 million during the year ended December 31, 2023. The increase was due to higher average interest-bearing balances and higher average yields.
The following table presents a reconciliation of net cash provided by operating activities, the most directly comparable financial measure calculated in accordance with GAAP, to free cash flow: Year Ended December 31, ( In thousands) 2023 2022 Net cash provided by operating activities $ 153,614 $ 53,656 Less: Capitalized software development costs and purchases of intangible assets (10,493) (4,562) Less: Purchases of property and equipment (3,191) (5,562) Plus: Taxes paid related to stock-based compensation equity awards 4,005 2,002 Plus: Public company costs (1) — 338 Plus: Acquisition transaction costs (2) — 185 Plus: Acquisition earn-out payment (3) 338 113 Free cash flow $ 144,273 $ 46,170 ________________ (1) Public company costs include costs associated with the establishment of our public company structure and processes, including consultant costs, a one-time fee associated with the set-up of our initial proxy statement, and fees paid to consultants and Deloitte for work in connection with remediation of the material weakness disclosed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021.
The following table presents a reconciliation of net cash provided by operating activities, the most directly comparable financial measure calculated in accordance with GAAP, to free cash flow: Year Ended December 31, ( In thousands) 2024 2023 Net cash provided by operating activities $ 285,513 $ 153,614 Less: Capitalized software development costs and purchases of intangible assets (9,024) (10,493) Less: Purchases of property and equipment (12,116) (3,191) Plus: Taxes paid related to stock-based compensation equity awards 9,790 4,005 Plus: Acquisition transaction costs (1) 774 — Plus: Acquisition earn-out payment (2) — 338 Free cash flow $ 274,937 $ 144,273 ________________ (1) Represents costs incurred related to acquisitions, including integration costs.
As a result, the benefits of our research and development investments may be difficult to forecast. We expect research and development to continue to be our largest operating expense, but expect that it will decline as a percentage of revenues over the long-term. Sales and Marketing.
As a result, the benefits of our research and development investments may be difficult to forecast. Sales and Marketing.
The increase in net cash provided by operating activities was mainly due to our generation of positive net income as discussed under the heading Adjusted EBITDA above. For the years ended December 31, 2023 and 2022, we generated $144.3 million and $46.2 million of free cash flow, respectively.
For the years ended December 31, 2024 and 2023, we generated $274.9 million and $144.3 million of free cash flow, respectively, representing an increase of $130.7 million. The increase in free cash flow was mainly attributable to the increase in net cash provided by operating activities. Constant Currency.
We believe that we have become the preeminent online destination for language learning due to our beautifully designed products, exceptional user engagement, and demonstrated learning efficacy.
We believe that we have become the preeminent online destination for language learning due to our beautifully designed products, exceptional user engagement, and demonstrated learning efficacy. Our Business Model 61 Table of Contents How We Generate Revenue We use a freemium business model that relies on a premium subscription offering, advertising, and in-app-purchases (IAPs) to produce revenue.
Income Taxes Deferred tax assets and liabilities are recognized principally for the expected tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts, using currently enacted tax rates.
Provided that the founders continue to provide services to us, stock-based compensation expense is recognized over the derived service period, regardless of whether the stock-price hurdles are achieved. 76 Table of Contents Income Taxes Deferred tax assets and liabilities are recognized principally for the expected tax consequences of temporary differences between the tax basis of assets and liabilities and their reported amounts, using currently enacted tax rates.
The decrease was due to a decrease in proceeds from exercises of stock options of $1.2 million, and taxes paid on the net-share settlements of share-based compensation awards of $11.5 million that did not occur in the prior period.
Cash provided by financing activities was $2.1 million for the year ended December 31, 2023 due to proceeds from exercises of stock options of $13.6 million, partially offset by taxes paid on the net-share settlements of share-based compensation awards of $11.5 million.