Castle BiosciencesCSTL +0.77%72 Gross Margin % is 75.46% as of Mar. 2026, which is 5% below its 10-year median of 79.53. GuruFocus rates CSTL with a GF Score™ of 72/100 and a GF Value™ of $29.15 (Modestly Undervalued). The stock has 4 warning signs investors should review. Among 195 Medical Diagnostics & Research companies, Castle Biosciences ranks better than 82.56% on this metric.
The historical rank and industry rank for Castle Biosciences's Gross Margin % or its related term are showing as below:
CSTL'
s Gross Margin % Range Over the Past 10 Years
Min: 64.21 Med: 79.53 Max: 85.91
Current: 77.88
During the past 9 years, the highestGross Margin % of Castle Biosciences was 85.91%. The lowest was 64.21%. And the median was 79.53%.
CSTL's Gross Margin % is ranked better than 82.56% of 195
companies
in the Medical Diagnostics & Research industry
Industry Median: 50.97
vs CSTL: 77.88
Castle Biosciences had a gross margin of 75.46% for the quarter that ended in Mar. 2026 => Durable competitive advantage
The 5-Year average Growth Rate of Gross Margin for Castle Biosciences was -0.90% per year.
Warren Buffett believes that firms with excellent long term economics tend to have consistently higher margins.
Durable competitive advantage creates a high Gross Margin % because of the freedom to price in excess of cost. Companies can be categorized by their Gross Margin %
1. Greater than 40% = Durable competitive advantage
2. Less than 40% = Competition eroding margins
3. Less than 20% = no sustainable competitive advantage
Consistency of Gross Margin is key
Castle Biosciences had a gross margin of 75.46% for the quarter that ended in Mar. 2026 => Durable competitive advantage
Be Aware
If a company loses its competitive advantages, usually its gross margin declines well before its sales declines. Watching Gross Margin % and Operating Margin % closely helps avoid value trap situations.
Castle Biosciences Gross Margin % Related Terms
Castle Biosciences Gross Margin % Historical Data
* Premium members only.
The historical data trend for Castle Biosciences's Gross Margin % can be seen below:
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
CSTL vs FLGT, MYGN, PRE: Gross Margin % Comparison
For the Diagnostics & Research subindustry, Castle Biosciences's Gross Margin %, along with its competitors' market caps and Gross Margin % data, can be viewed below:
* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.
Castle Biosciences Gross Margin % vs Medical Diagnostics & Research Industry
For the Medical Diagnostics & Research industry and Healthcare sector, Castle Biosciences's Gross Margin % distribution charts can be found below:
* The bar in red indicates where Castle Biosciences's Gross Margin % falls into.
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
A positive Gross Profit is only the first step for a company to make a net profit. The gross profit needs to be big enough to also cover related labor, equipment, rental, marketing/advertising, research and development and a lot of other costs in selling the products.
Castle Biosciences (CSTL) has a Gross Margin % of 75.46% as of Mar. 2026. Gross margin is the ratio of total gross profit to net sales. View historical data on Castle Biosciences and its competitors. This is near median its historical median of 79.53. Over the past decade, Castle Biosciences' Gross Margin % has ranged from 64.21 to 85.91. According to the industry distribution chart, Castle Biosciences ranks #34 out of 195 companies in the Medical Diagnostics & Research industry, placing it in the top 17.4%.
Is Castle Biosciences' Gross Margin % too high?
Castle Biosciences' current Gross Margin % of 75.46% is near median its 10-year median of 79.53. Over the past 10 years, this metric has ranged from a low of 64.21 to a high of 85.91. The Medical Diagnostics & Research industry median Gross Margin % is 50.97. Castle Biosciences' value of 75.46% is 48% above this industry median. Based on the distribution chart, Castle Biosciences ranks #34 out of 195 companies in the Medical Diagnostics & Research industry, which is in the top quartile — a strong position relative to peers. Overall, Castle Biosciences has a GF Score™ of 72/100 and is considered Modestly Undervalued, reflecting its overall financial health beyond just this single metric.
How does Castle Biosciences' Gross Margin % compare to FLGT and MYGN?
According to the Medical Diagnostics & Research industry distribution chart, Castle Biosciences ranks #34 out of 195 companies for Gross Margin %. This places Castle Biosciences in the top 17% of its industry — outperforming the majority of peers. The industry median Gross Margin % is 50.97. Castle Biosciences' value of 75.46% is 48% above this benchmark. Historically, Castle Biosciences' own Gross Margin % has ranged from 64.21 to 85.91 over the past decade. While the company's 10-year median is 79.53 vs. the industry median of 50.97, Castle Biosciences has consistently been above the industry average. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good Gross Margin % for a Medical Diagnostics & Research company?
The median Gross Margin % among Medical Diagnostics & Research companies is 50.97, based on 195 companies in the industry. Companies in the top quartile (top 25%) have a Gross Margin % significantly above this median, while those in the bottom quartile fall well below. However, Gross Margin % should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Castle Biosciences's current Gross Margin % of 75.46% is 48% above the industry median. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high Gross Margin % mean?
A high Gross Margin % can signal that a stock is expensive relative to its fundamentals. Gross margin is the ratio of total gross profit to net sales. View historical data on Castle Biosciences and its competitors. For the Medical Diagnostics & Research industry, the median Gross Margin % is 50.97 — values significantly above this may indicate overvaluation, while values below may suggest a bargain or underlying issues. Castle Biosciences's current Gross Margin % is 75.46%, which is near median its own 10-year median of 79.53. However, context matters — high-growth companies often justify higher valuations. Always evaluate alongside other metrics like GF Score™ and GF Value™.
Is Castle Biosciences stock overvalued right now?
Based on GuruFocus' analysis, Castle Biosciences (CSTL) is currently considered Modestly Undervalued. The stock's GF Value™ is $29.15, compared to a current price of $22.29 — trading 23.5% below its estimated fair value. The current Gross Margin % is 75.46%, which is near median its 10-year median of 79.53 and 48% above the Medical Diagnostics & Research industry median of 50.97. Castle Biosciences' overall GF Score™ is 72/100 with 4 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is Gross Margin % calculated?
Gross Margin % is calculated from a company's financial statements. For Castle Biosciences (CSTL), the current Gross Margin % is 75.46% as of Mar. 2026. GuruFocus calculates this using data sourced from SEC filings and annual reports. See the calculation section and 30-year financial data on this page for the full breakdown.
Is Castle Biosciences (CSTL) Overvalued in 2026?
Based on GuruFocus' analysis, Castle Biosciences stock appears to be undervalued.
The current stock price of $22.29 is trading 23.5% below its estimated GF Value™ of $29.15.
GuruFocus considers Castle Biosciences to be Modestly Undervalued.
Key valuation signals for CSTL:
Gross Margin %: 75.46% (near median its 10-year median of 79.53)
GF Value™: $29.15 vs. price of $22.29 (23.5% below fair value)
Industry Position: 48% above the Medical Diagnostics & Research median (#34 of 195)
No single metric tells the full story. See the CSTL stock analysis page for a complete view including 30-year financials, guru trades, and insider activity.
Castle Biosciences Inc is a molecular diagnostics company. The group provides test solutions for the diagnosis and treatment of dermatologic cancers, Barrett's esophagus (BE), and uveal melanoma. The product portfolio of the company includes DecisionDx-Melanoma, a risk stratification gene expression profile (GEP) test; DecisionDx-SCC, a risk stratification test for cutaneous squamous cell carcinoma; MyPath Melanoma, a diagnostic GEP test for use in patients with difficult-to-diagnose melanocytic lesions; and TissueCypher, a test to predict future development of progression of high-grade dysplasia and/or esophageal cancer. The company derives revenues through the delivery of test reports for its molecular diagnostic tests.
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