Castle Biosciences, Inc.

CSTLNASDAQHealthcare● Active

$20.29

$-0.72(-3.43%)

Market Cap$615394726

P/E Ratio—

52W High$44.28

52W Low$14.59

Avg Volume383K

Open$20.94

Beta1.02

Free Cash Flow Financials Revenue

Castle Biosciences, Inc. (CSTL) Free Cash Flow & Analysis

Annual & trailing free cash flow, FCF margin, YoY change, valuation ratios, and peer context.

CSTL · free cash flow · updated Jun 8, 2026

Core FCF metrics

CSTL · FCF · TTM · margin & CAGR

Free cash flow was $28.3M for FY2025 (fiscal year ending 2025-12-31), down 22.5% year-over-year The FCF margin was 8.2%. Five-year CAGR stands at +40.8%.

FY2025 Free Cash Flow$28.3M▼ -22.5% YoY

Trailing 12M (TTM)$4.5Mtrailing 4 quarters sum

FCF Margin8.2%$28.3M ÷ revenue

3-Year CAGRN/AN/A — contains negative FCF

5-Year CAGR+40.8%FY2020 → FY2025

FormulaFCF = Operating Cash Flow − Capital ExpendituresTTM = trailing 4 quarters sumCAGR → N/A if either endpoint ≤ 0

Source: FMP /cash-flow-statement · SEC 10-K / 10-Q · USDUpdated: Jun 8, 2026

Annual free cash flow history

FCF ($B, upper) · YoY Growth % (lower)

Positive FCFNegative FCF

Free Cash Flow

YoY Growth %

Annual free cash flow data

CSTL · free cash flow history · annual / quarterly

Fiscal YearOperating CFCapExFree Cash FlowYoY ChangeFCF Margin

FY2025Latest$64.3M(36M)$28.3M▼ 22.5%8.2%

FY2024$64.9M(28M)$36.5M▲ +289.8%11.0%

FY2023−$5.6M(14M)−$19.2M▲ +59.3%-8.8%

FY2022−$41.7M(6M)−$47.3M▼ 110.5%-34.5%

FY2021−$19.0M(3M)−$22.5M▼ 539.3%-23.9%

FCF = Operating Cash Flow − Capital Expenditures · CapEx shown as (negative) · Source: SEC filings via FMP

FCF valuation metrics

CSTL · P/FCF · FCF yield · FCF per share

Castle Biosciences, Inc. (CSTL) trades at a FCF yield of 0.74% and a price-to-free-cash-flow ratio of 126.8x. FCF per share stands at $0.16, calculated using trailing twelve-month FCF divided by basic weighted-average shares outstanding.

FCF Yield (TTM)

0.74%

Free Cash Flow ÷ Market Cap

per FMP freeCashFlowYieldTTM definition

FCF per Share (TTM)

$0.16

TTM FCF ÷ Shares Outstanding

Price / FCF

x126.8

Share Price ÷ FCF per Share

EV / FCF (TTM)

x130.0

Enterprise Value basis

Source: FMP /key-metrics-ttm · /cash-flow-statement Q · /income-statementFY2025 · 2025-12-31

Cash flow statement summary

CSTL · cash flow statement · operating / investing / financing

For FY2025, Castle Biosciences, Inc. generated $64.3M in operating cash flow and spent 36M in capital expenditures, yielding $28.3M in free cash flow.

Operating Activities

+$64.3M

Cash from core business operations

2025-12-31

Investing Activities

−$60.4M

CapEx, acquisitions & investments

2025-12-31

Financing Activities

−$7.0M

Buybacks, dividends & debt

2025-12-31

FCF FormulaOperating CF ($64.3M) − |CapEx| (36M) = FCF ($28.3M)

For the complete Operating / Investing / Financing line-item breakdown:

View Full Cash Flow Statement →

Free cash flow vs peers (Healthcare)

CSTL vs peers · FCF

#CompanyFree Cash FlowYoYFCF MarginRelative

Castle Biosciences, Inc.YOU

CSTL

$28.3M-22.5%8.2%

UnitedHealth Group Incorporated

UNH

$16.07B-22.4%3.6%

82%

Eli Lilly and Company

LLY

$8.97B+2065.6%13.8%

46%

Healthcare · Sorted by FCF · FMP /cash-flow-statementFull FCF Rankings →

About Free Cash Flow & Methodology

Castle Biosciences, Inc. (CSTL) reported free cash flow of $28.3M for FY2025 (fiscal year ending 2025-12-31), down 22.5% year-over-year. The FCF margin was 8.2%.

Based on available data, Castle Biosciences, Inc. has maintained positive free cash flow for at least 4 fiscal year(s). FCF peaked at $36.5M in FY2024. The 5-year CAGR stands at +40.8%.

Castle Biosciences, Inc.'s FCF yield is 0.74% and price-to-FCF ratio is 126.8x for FY2025, based on the latest available data.

Data sourced from FMP /cash-flow-statement · SEC 10-K / 10-Q · USD.

Q&A and summaries align with SEC 10-K/10-Q cash flow disclosures and FMP /cash-flow-statement where noted.

Revenue Financial statements Net income Earnings Forecast Price history Market cap Cash on hand P/E ratio

Frequently asked questions

CSTL free cash flow · 8 questions

Castle Biosciences, Inc. free cash flow was $28.3M for FY2025, down 22.5% year-over-year. On a trailing twelve-month (TTM) basis, free cash flow stands at $4.5M.

CSTL free cash flowCSTL FCFCSTL FCF 2025CSTL free cash flow TTM

▸ Source: FMP /cash-flow-statement · US GAAP · Castle Biosciences, Inc. · Castle Biosciences, Inc. SEC 10-K & 10-Q filings · US GAAP · Last updated: Jun 8, 2026