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Side-by-side financial comparison of CASTLE BIOSCIENCES INC (CSTL) and Heartflow, Inc. (HTFL). Click either name above to swap in a different company.
CASTLE BIOSCIENCES INC is the larger business by last-quarter revenue ($87.0M vs $46.3M, roughly 1.9× Heartflow, Inc.). CASTLE BIOSCIENCES INC produced more free cash flow last quarter ($19.7M vs $-4.2M).
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.
HeartFlow, Inc. develops non-invasive cardiovascular diagnostic solutions for global healthcare providers. Its core product uses CT scan data to build 3D coronary artery models, assess blood flow to detect blockages, and support clinicians in making personalized heart disease treatment decisions without invasive procedures.
CSTL vs HTFL — Head-to-Head
Income Statement — Q4 FY2025 vs Q3 FY2025
| Metric | | |
|---|---|---|
| Revenue | $87.0M | $46.3M |
| Net Profit | — | $-50.9M |
| Gross Margin | 79.0% | 76.5% |
| Operating Margin | -4.4% | -32.6% |
| Net Margin | — | -109.9% |
| Revenue YoY | 0.8% | — |
| Net Profit YoY | — | — |
| EPS (diluted) | $-0.06 | $-1.04 |
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.
| Q4 25 | $87.0M | — | ||
| Q3 25 | $83.0M | $46.3M | ||
| Q2 25 | $86.2M | $43.4M | ||
| Q1 25 | $88.0M | — | ||
| Q4 24 | $86.3M | — | ||
| Q3 24 | $85.8M | — | ||
| Q2 24 | $87.0M | — | ||
| Q1 24 | $73.0M | — |
| Q4 25 | — | — | ||
| Q3 25 | $-501.0K | $-50.9M | ||
| Q2 25 | $4.5M | $-9.2M | ||
| Q1 25 | $-25.8M | — | ||
| Q4 24 | — | — | ||
| Q3 24 | $2.3M | — | ||
| Q2 24 | $8.9M | — | ||
| Q1 24 | $-2.5M | — |
| Q4 25 | 79.0% | — | ||
| Q3 25 | 77.5% | 76.5% | ||
| Q2 25 | 79.5% | 75.5% | ||
| Q1 25 | 81.4% | — | ||
| Q4 24 | 81.3% | — | ||
| Q3 24 | 81.8% | — | ||
| Q2 24 | 83.3% | — | ||
| Q1 24 | 81.0% | — |
| Q4 25 | -4.4% | — | ||
| Q3 25 | -8.2% | -32.6% | ||
| Q2 25 | -4.9% | -31.6% | ||
| Q1 25 | -31.7% | — | ||
| Q4 24 | 4.7% | — | ||
| Q3 24 | 5.9% | — | ||
| Q2 24 | 5.8% | — | ||
| Q1 24 | -7.5% | — |
| Q4 25 | — | — | ||
| Q3 25 | -0.6% | -109.9% | ||
| Q2 25 | 5.2% | -21.2% | ||
| Q1 25 | -29.4% | — | ||
| Q4 24 | — | — | ||
| Q3 24 | 2.6% | — | ||
| Q2 24 | 10.3% | — | ||
| Q1 24 | -3.5% | — |
| Q4 25 | $-0.06 | — | ||
| Q3 25 | $-0.02 | $-1.04 | ||
| Q2 25 | $0.15 | $-1.46 | ||
| Q1 25 | $-0.90 | — | ||
| Q4 24 | $0.32 | — | ||
| Q3 24 | $0.08 | — | ||
| Q2 24 | $0.31 | — | ||
| Q1 24 | $-0.09 | — |
Balance Sheet & Financial Strength
Snapshot of each company's liquidity, leverage and book value from the latest quarter.
| Metric | | |
|---|---|---|
| Cash + ST InvestmentsLiquidity on hand | $299.5M | $291.2M |
| Total DebtLower is stronger | $10.1M | — |
| Stockholders' EquityBook value | $470.9M | $254.6M |
| Total Assets | $578.6M | $364.4M |
| Debt / EquityLower = less leverage | 0.02× | — |
8-quarter trend — quarters aligned by calendar period.
| Q4 25 | $299.5M | — | ||
| Q3 25 | $287.5M | $291.2M | ||
| Q2 25 | $275.9M | $80.2M | ||
| Q1 25 | $275.2M | — | ||
| Q4 24 | $293.1M | — | ||
| Q3 24 | $95.0M | — | ||
| Q2 24 | $85.6M | — | ||
| Q1 24 | $82.9M | — |
| 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 | — |
| Q4 25 | $470.9M | — | ||
| Q3 25 | $467.0M | $254.6M | ||
| Q2 25 | $455.4M | $-894.8M | ||
| Q1 25 | $440.3M | — | ||
| Q4 24 | $455.8M | — | ||
| Q3 24 | $441.1M | — | ||
| Q2 24 | $423.9M | — | ||
| Q1 24 | $402.5M | — |
| Q4 25 | $578.6M | — | ||
| Q3 25 | $562.8M | $364.4M | ||
| Q2 25 | $544.7M | $159.4M | ||
| Q1 25 | $501.7M | — | ||
| Q4 24 | $531.2M | — | ||
| Q3 24 | $514.6M | — | ||
| Q2 24 | $487.3M | — | ||
| Q1 24 | $458.5M | — |
| 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 | | |
|---|---|---|
| Operating Cash FlowLast quarter | $26.9M | $-3.0M |
| Free Cash FlowOCF − Capex | $19.7M | $-4.2M |
| FCF MarginFCF / Revenue | 22.7% | -9.1% |
| Capex IntensityCapex / Revenue | 8.3% | 2.7% |
| Cash ConversionOCF / Net Profit | — | — |
| TTM Free Cash FlowTrailing 4 quarters | $28.3M | — |
8-quarter trend — quarters aligned by calendar period.
| Q4 25 | $26.9M | — | ||
| Q3 25 | $22.6M | $-3.0M | ||
| Q2 25 | $20.8M | $-40.5M | ||
| Q1 25 | $-6.0M | — | ||
| Q4 24 | $24.4M | — | ||
| Q3 24 | $23.3M | — | ||
| Q2 24 | $24.0M | — | ||
| Q1 24 | $-6.8M | — |
| Q4 25 | $19.7M | — | ||
| Q3 25 | $7.8M | $-4.2M | ||
| Q2 25 | $11.6M | $-42.4M | ||
| Q1 25 | $-10.8M | — | ||
| Q4 24 | $16.8M | — | ||
| Q3 24 | $17.0M | — | ||
| Q2 24 | $18.8M | — | ||
| Q1 24 | $-16.0M | — |
| Q4 25 | 22.7% | — | ||
| Q3 25 | 9.4% | -9.1% | ||
| Q2 25 | 13.4% | -97.6% | ||
| Q1 25 | -12.2% | — | ||
| Q4 24 | 19.5% | — | ||
| Q3 24 | 19.8% | — | ||
| Q2 24 | 21.6% | — | ||
| Q1 24 | -21.9% | — |
| Q4 25 | 8.3% | — | ||
| Q3 25 | 17.9% | 2.7% | ||
| Q2 25 | 10.7% | 4.4% | ||
| Q1 25 | 5.4% | — | ||
| Q4 24 | 8.8% | — | ||
| Q3 24 | 7.4% | — | ||
| Q2 24 | 6.0% | — | ||
| Q1 24 | 12.5% | — |
| 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
CSTL
| Dermatologic | $48.6M | 56% |
| Non Dermatologic | $38.4M | 44% |
HTFL
Segment breakdown not available.
