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Side-by-side financial comparison of Amplitude, Inc. (AMPL) and CASTLE BIOSCIENCES INC (CSTL). Click either name above to swap in a different company.

Amplitude, Inc. is the larger business by last-quarter revenue ($91.4M vs $87.0M, roughly 1.1× CASTLE BIOSCIENCES INC). On growth, Amplitude, Inc. posted the faster year-over-year revenue change (17.0% vs 0.8%). CASTLE BIOSCIENCES INC produced more free cash flow last quarter ($19.7M vs $12.7M). Over the past eight quarters, Amplitude, Inc.'s revenue compounded faster (12.2% CAGR vs 9.2%).

Amplitude is an American publicly traded company that develops digital analytics software. The company was listed publicly on the Nasdaq stock exchange under the ticker symbol AMPL on September 28, 2021.

Castle Biosciences Inc. is a commercial-stage diagnostic firm that develops and markets proprietary, clinically actionable tests for dermatological conditions such as melanoma and other skin cancers, plus rare diseases. It operates mainly in the U.S. healthcare market, focusing on segments with high unmet need for more accurate diagnostics to guide treatment choices.

AMPL vs CSTL — Head-to-Head

Bigger by revenue
AMPL
AMPL
1.1× larger
AMPL
$91.4M
$87.0M
CSTL
Growing faster (revenue YoY)
AMPL
AMPL
+16.2% gap
AMPL
17.0%
0.8%
CSTL
More free cash flow
CSTL
CSTL
$7.1M more FCF
CSTL
$19.7M
$12.7M
AMPL
Faster 2-yr revenue CAGR
AMPL
AMPL
Annualised
AMPL
12.2%
9.2%
CSTL

Income Statement — Q4 FY2025 vs Q4 FY2025

Metric
AMPL
AMPL
CSTL
CSTL
Revenue
$91.4M
$87.0M
Net Profit
$-17.7M
Gross Margin
74.6%
79.0%
Operating Margin
-18.3%
-4.4%
Net Margin
-19.3%
Revenue YoY
17.0%
0.8%
Net Profit YoY
45.8%
EPS (diluted)
$-0.13
$-0.06

Green = leading value per metric. Periods may differ when fiscal calendars don't align.

8-Quarter Revenue & Profit Trend

Side-by-side quarterly history. Quarters aligned by calendar period so offset fiscal years line up.

Revenue
AMPL
AMPL
CSTL
CSTL
Q4 25
$91.4M
$87.0M
Q3 25
$88.6M
$83.0M
Q2 25
$83.3M
$86.2M
Q1 25
$80.0M
$88.0M
Q4 24
$78.1M
$86.3M
Q3 24
$75.2M
$85.8M
Q2 24
$73.3M
$87.0M
Q1 24
$72.6M
$73.0M
Net Profit
AMPL
AMPL
CSTL
CSTL
Q4 25
$-17.7M
Q3 25
$-24.0M
$-501.0K
Q2 25
$-24.7M
$4.5M
Q1 25
$-22.2M
$-25.8M
Q4 24
$-32.6M
Q3 24
$-16.9M
$2.3M
Q2 24
$-23.4M
$8.9M
Q1 24
$-21.5M
$-2.5M
Gross Margin
AMPL
AMPL
CSTL
CSTL
Q4 25
74.6%
79.0%
Q3 25
73.9%
77.5%
Q2 25
72.6%
79.5%
Q1 25
74.7%
81.4%
Q4 24
74.7%
81.3%
Q3 24
75.1%
81.8%
Q2 24
73.4%
83.3%
Q1 24
74.0%
81.0%
Operating Margin
AMPL
AMPL
CSTL
CSTL
Q4 25
-18.3%
-4.4%
Q3 25
-26.0%
-8.2%
Q2 25
-29.0%
-4.9%
Q1 25
-26.8%
-31.7%
Q4 24
-41.2%
4.7%
Q3 24
-21.4%
5.9%
Q2 24
-31.7%
5.8%
Q1 24
-29.0%
-7.5%
Net Margin
AMPL
AMPL
CSTL
CSTL
Q4 25
-19.3%
Q3 25
-27.1%
-0.6%
Q2 25
-29.6%
5.2%
Q1 25
-27.8%
-29.4%
Q4 24
-41.7%
Q3 24
-22.4%
2.6%
Q2 24
-31.9%
10.3%
Q1 24
-29.5%
-3.5%
EPS (diluted)
AMPL
AMPL
CSTL
CSTL
Q4 25
$-0.13
$-0.06
Q3 25
$-0.18
$-0.02
Q2 25
$-0.19
$0.15
Q1 25
$-0.17
$-0.90
Q4 24
$-0.25
$0.32
Q3 24
$-0.14
$0.08
Q2 24
$-0.19
$0.31
Q1 24
$-0.18
$-0.09

Balance Sheet & Financial Strength

Snapshot of each company's liquidity, leverage and book value from the latest quarter.

Metric
AMPL
AMPL
CSTL
CSTL
Cash + ST InvestmentsLiquidity on hand
$192.0M
$299.5M
Total DebtLower is stronger
$10.1M
Stockholders' EquityBook value
$245.3M
$470.9M
Total Assets
$420.7M
$578.6M
Debt / EquityLower = less leverage
0.02×

8-quarter trend — quarters aligned by calendar period.

Cash + ST Investments
AMPL
AMPL
CSTL
CSTL
Q4 25
$192.0M
$299.5M
Q3 25
$189.2M
$287.5M
Q2 25
$208.1M
$275.9M
Q1 25
$209.0M
$275.2M
Q4 24
$241.1M
$293.1M
Q3 24
$319.9M
$95.0M
Q2 24
$318.3M
$85.6M
Q1 24
$316.1M
$82.9M
Total Debt
AMPL
AMPL
CSTL
CSTL
Q4 25
$10.1M
Q3 25
$10.0M
Q2 25
$10.0M
Q1 25
$10.0M
Q4 24
$10.0M
Q3 24
$10.0M
Q2 24
$10.0M
Q1 24
$10.0M
Stockholders' Equity
AMPL
AMPL
CSTL
CSTL
Q4 25
$245.3M
$470.9M
Q3 25
$262.2M
$467.0M
Q2 25
$279.5M
$455.4M
Q1 25
$289.5M
$440.3M
Q4 24
$296.6M
$455.8M
Q3 24
$290.0M
$441.1M
Q2 24
$287.3M
$423.9M
Q1 24
$289.2M
$402.5M
Total Assets
AMPL
AMPL
CSTL
CSTL
Q4 25
$420.7M
$578.6M
Q3 25
$438.1M
$562.8M
Q2 25
$456.6M
$544.7M
Q1 25
$445.8M
$501.7M
Q4 24
$445.9M
$531.2M
Q3 24
$445.6M
$514.6M
Q2 24
$445.4M
$487.3M
Q1 24
$437.9M
$458.5M
Debt / Equity
AMPL
AMPL
CSTL
CSTL
Q4 25
0.02×
Q3 25
0.02×
Q2 25
0.02×
Q1 25
0.02×
Q4 24
0.02×
Q3 24
0.02×
Q2 24
0.02×
Q1 24
0.02×

Cash Flow & Capital Efficiency

How much cash each business actually produces after reinvestment. Cash flow is harder to manipulate than net income.

Metric
AMPL
AMPL
CSTL
CSTL
Operating Cash FlowLast quarter
$12.8M
$26.9M
Free Cash FlowOCF − Capex
$12.7M
$19.7M
FCF MarginFCF / Revenue
13.8%
22.7%
Capex IntensityCapex / Revenue
0.2%
8.3%
Cash ConversionOCF / Net Profit
TTM Free Cash FlowTrailing 4 quarters
$28.2M
$28.3M

8-quarter trend — quarters aligned by calendar period.

Operating Cash Flow
AMPL
AMPL
CSTL
CSTL
Q4 25
$12.8M
$26.9M
Q3 25
$5.0M
$22.6M
Q2 25
$20.1M
$20.8M
Q1 25
$-8.0M
$-6.0M
Q4 24
$3.2M
$24.4M
Q3 24
$6.2M
$23.3M
Q2 24
$9.2M
$24.0M
Q1 24
$-48.0K
$-6.8M
Free Cash Flow
AMPL
AMPL
CSTL
CSTL
Q4 25
$12.7M
$19.7M
Q3 25
$4.5M
$7.8M
Q2 25
$19.5M
$11.6M
Q1 25
$-8.5M
$-10.8M
Q4 24
$2.4M
$16.8M
Q3 24
$6.2M
$17.0M
Q2 24
$8.6M
$18.8M
Q1 24
$-405.0K
$-16.0M
FCF Margin
AMPL
AMPL
CSTL
CSTL
Q4 25
13.8%
22.7%
Q3 25
5.1%
9.4%
Q2 25
23.4%
13.4%
Q1 25
-10.6%
-12.2%
Q4 24
3.1%
19.5%
Q3 24
8.2%
19.8%
Q2 24
11.8%
21.6%
Q1 24
-0.6%
-21.9%
Capex Intensity
AMPL
AMPL
CSTL
CSTL
Q4 25
0.2%
8.3%
Q3 25
0.5%
17.9%
Q2 25
0.6%
10.7%
Q1 25
0.5%
5.4%
Q4 24
1.0%
8.8%
Q3 24
0.0%
7.4%
Q2 24
0.8%
6.0%
Q1 24
0.5%
12.5%
Cash Conversion
AMPL
AMPL
CSTL
CSTL
Q4 25
Q3 25
Q2 25
4.60×
Q1 25
Q4 24
Q3 24
10.29×
Q2 24
2.69×
Q1 24

Financial Flow Comparison

Revenue → gross profit → operating profit → net profit for each company.

Revenue Breakdown by Segment

AMPL
AMPL

US$55.8M61%
International$35.7M39%

CSTL
CSTL

Dermatologic$48.6M56%
Non Dermatologic$38.4M44%

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