Castle Biosciences Inc key statistics and ratios

In fiscal 2025, Castle Biosciences Inc had return on equity of -5.2%, an operating margin of -12.4%, debt equal to 2.2% of equity and a current ratio of 5.26. Each ratio below is calculated from the figures on its income statement, balance sheet and cash flow pages.

Financial ratios

US$ thousands unless shown otherwise. Fiscal years, plus the last twelve months (LTM) when newer.

Castle Biosciences Inc: financial ratios, annual
Fiscal year	2018Dec 2018	2019Dec 2019	2020Dec 2020	2021Dec 2021	2022Dec 2022	2023Dec 2023	2024Dec 2024	2025Dec 2025	LTMJun 2026
Gross margin	76.8%	85.9%	84.5%	83.2%	76.6%	79.5%	81.9%	79.4%	77.3%
Operating margin	−16.8%	14.1%	−10.4%	−42.6%	−53.2%	−30.9%	2.6%	−12.4%	−9.0%
Net margin	−27.9%	10.2%	−16.4%	−33.3%	−49.0%	−26.1%	5.5%	−7.0%	−5.4%
Free-cash-flow margin	−55.2%	11.7%	8.2%	−23.9%	−34.5%	−8.8%	11.0%	8.2%	−0.1%
Return on equity	—	37.0%	−4.1%	−7.6%	−16.6%	−14.5%	4.3%	−5.2%	−4.1%
Return on assets	−28.4%	7.4%	−3.7%	−6.9%	−14.8%	−12.8%	3.7%	−4.4%	−3.4%
Asset turnover	1.02	0.73	0.22	0.21	0.30	0.49	0.67	0.62	0.63
Current ratio	2.69	7.63	20.58	14.21	8.09	6.20	7.29	5.26	6.04
Debt to equity	—	31.4%	0.0%	0.0%	0.0%	0.0%	2.2%	2.2%	2.2%
Interest cover (operating income ÷ interest)	n/m	1.6x	n/m	n/m	n/m	n/m	15.0x	n/m	n/m
R&D as % of revenue	21.3%	14.2%	21.2%	31.5%	32.8%	24.4%	15.7%	15.1%	15.5%
SG&A as % of revenue	72.3%	57.5%	76.8%	92.2%	104.4%	82.0%	60.2%	66.6%	68.2%
Capital spending as % of revenue	1.2%	1.8%	7.6%	3.7%	4.1%	6.2%	8.5%	10.5%	12.1%
Free cash flow ÷ net income	—	115.2%	—	—	—	—	200.3%	—	—

US$ thousands unless shown otherwise. Fiscal quarters.

Castle Biosciences Inc: financial ratios, quarterly
Quarter	2024 Q3Sept 2024	2024 Q4Dec 2024	2025 Q1Mar 2025	2025 Q2Jun 2025	2025 Q3Sept 2025	2025 Q4Dec 2025	2026 Q1Mar 2026	2026 Q2Jun 2026
Gross margin	81.8%	81.3%	81.4%	79.5%	77.5%	79.0%	75.5%	77.1%
Operating margin	5.9%	4.7%	−31.7%	−4.9%	−8.2%	−4.4%	−22.0%	−3.0%
Net margin	2.6%	11.1%	−29.4%	5.2%	−0.6%	−2.7%	−17.4%	−2.0%
Free-cash-flow margin	19.8%	19.5%	−12.2%	13.4%	9.4%	22.7%	−41.3%	6.3%
Current ratio	7.78	7.29	9.37	6.85	6.47	5.26	6.75	6.04
Debt to equity	2.3%	2.2%	2.3%	2.2%	2.2%	2.1%	2.2%	2.1%
R&D as % of revenue	14.4%	13.6%	14.3%	14.8%	15.6%	15.5%	17.2%	14.0%
SG&A as % of revenue	58.9%	57.9%	66.6%	67.4%	67.3%	65.2%	77.6%	63.9%

Returns use average equity or assets over the year. Return on equity is left blank when equity is negative or so small that the ratio says nothing (above ±200%); interest cover is left blank above 200 times. Price-based ratios such as P/E are on the valuation page.

Financial health

5 of 6 checks passed · June 30, 2026

What it owns · $561m

Short-term assets $341mLonger-term assets $220m

What it owes, and who funded it · $561m

Short-term liabilities $57mLonger-term liabilities $35mShareholders' equity $470m

Short-term assets cover short-term liabilities $341m of assets due within a year against $57m of liabilities due within a year.
Short-term assets cover long-term liabilities $341m short-term assets against $35m of longer-dated liabilities.
More cash than debt $62m of cash against $10m of debt.
Debt below 40% of shareholders' equity Debt is 2% of equity.
Debt burden no higher than five years ago Five-year comparison not available. Not assessable.
A year's operating cash flow covers at least 20% of debt $43m of operating cash flow against $10m of debt.
Operating profit covers interest at least five times over Operating income of −$32m against $375,000 of interest.

From Castle Biosciences Inc's latest balance sheet as filed. Checks are fixed, documented rules (methodology), counted only where the company reports the figures — a dot means the filing doesn't break the item out. Descriptions of reported data, not advice.

Moat

32 /100

Weak moat

How hard Castle Biosciences's competitive advantage looks for rivals to wear away, judged from 8 years of its own filings: returns on capital, pricing power, profit durability, cash conversion and discipline.

Returns on capital 4 / 20

Cash operating profit has been a median 4.9% of total assets over 7 years.
Pricing power 19 / 20

Gross margin has been a median 81.4%, moving by 3.3 percentage points (standard deviation) across 8 years.
Durability 10 / 20

Operating margin has been a median -7.8%; its worst year was -57.9%.
Cash conversion 4 / 20

Free cash flow was positive in 3 of 8 years, at a median -5.6% of revenue.
Discipline 0 / 20

The diluted share count rose 32.0% over five years; stock-based pay has been a median 15.6% of revenue.

AI disruption exposure: Medium. In this industry, AI could change how the product is made or sold, without replacing the core asset. The score above includes a 5-point deduction for that exposure (37 before it).

A rules-based reading of reported figures, not a forecast and not investment advice. How the score is built: methodology.

Compare with peers

Head to head: CSTL vs FLGT CSTL vs TWST CSTL vs SDGR

More: Life Sciences Tools & Services stocks compared, Health Care sector, rankings of US companies

Figures from Castle Biosciences Inc's SEC filings (10-K and 10-Q), retrieved October 29, 2026. How we read and check them: methodology and data sources. Not investment advice. Back to Castle Biosciences Inc.