Which BSA formula should I use?

Mosteller is widely adopted for its simplicity and close agreement with more complex formulas. Du Bois & Du Bois, Haycock, Gehan & George, and Boyd are also accepted in the literature. Choose based on local protocols.

Does unit choice affect the result?

No. Inputs are converted internally to centimeters and kilograms before calculation. Metric and imperial inputs yield identical BSA values.

What is the typical BSA range for adults?

Adult BSA usually ranges between about 1.5 and 2.2 m², but values outside this range can occur depending on body size.

Is this calculator suitable for children?

Yes. Haycock and Mosteller are frequently used in pediatrics. Always follow pediatric guidelines and clinical judgment.

Is BSA a substitute for medical advice?

No. This tool is for educational and informational purposes only and does not replace professional medical advice, diagnosis, or treatment.

How are rounding and precision handled?

You can choose 2–3 decimal places. Calculations are performed in double precision and rounded only for display.

Can I share or save my inputs?

Yes. The page updates the URL with your inputs so you can bookmark or share a link that recreates the result.

Body Surface Area (BSA) Calculator

Use this professional BSA calculator to estimate body surface area in square meters (m²) from height and weight. It is designed for clinicians, researchers, and students, supports both metric and imperial units, and offers multiple peer‑reviewed formulas to fit your protocol.

Authoritative Data Sources and Methodology

This calculator implements widely cited, peer‑reviewed BSA equations. Primary references:

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098. DOI: 10.1056/NEJM198710223171717.
Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17(6):863–871.
Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: A height-weight formula validated in infants, children, and adults. J Pediatr. 1978;93(1):62–66.
Gehan EA, George SL. Estimation of human body surface area from height and weight. Cancer Chemother Rep. 1970;54(4):225–235.
Boyd E. The growth of the surface area of the human body. University of Minnesota Press; 1935.

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formulas Explained

Mosteller

$$ \mathrm{BSA} = \sqrt{\frac{H_{\mathrm{cm}} \times W_{\mathrm{kg}}}{3600}} $$

Du Bois & Du Bois

$$ \mathrm{BSA} = 0.007184 \times H_{\mathrm{cm}}^{0.725} \times W_{\mathrm{kg}}^{0.425} $$

Haycock

$$ \mathrm{BSA} = 0.024265 \times H_{\mathrm{cm}}^{0.3964} \times W_{\mathrm{kg}}^{0.5378} $$

Gehan \& George

$$ \mathrm{BSA} = 0.0235 \times H_{\mathrm{cm}}^{0.42246} \times W_{\mathrm{kg}}^{0.51456} $$

Boyd

$$ \mathrm{BSA} = 0.0003207 \times H_{\mathrm{cm}}^{0.3} \times W_{\mathrm{kg}}^{\,0.7285 - 0.0188\,\log_{10}\!\left(W_{\mathrm{kg}}\right)} $$

Glossary of Variables

H_cm (Height): Stature in centimeters. The calculator internally converts inches to centimeters when using imperial units.
W_kg (Weight): Body mass in kilograms. Pounds are converted to kilograms internally.
BSA: Body Surface Area expressed in square meters (m²).
Formula: The specific peer‑reviewed equation used to calculate BSA.
Rounding: Number of decimals shown; calculations use double precision before rounding for display.

How It Works: A Step-by-Step Example

Inputs: Height = 170 cm, Weight = 70 kg, Formula = Mosteller.

Using the Mosteller equation:

$$ \mathrm{BSA} = \sqrt{\frac{170 \times 70}{3600}} = \sqrt{ \frac{11900}{3600} } = \sqrt{3.3056} \approx 1.818\,\mathrm{m}^2 $$

Rounded to two decimals: 1.82 m².

Frequently Asked Questions (FAQ)

What is Body Surface Area (BSA)?

BSA is a measure of the total surface area of the human body. It is used to normalize physiological metrics and to determine certain medication dosages.

Which BSA formula is “best”?

There is no universal best formula. Mosteller is popular for its simplicity and close agreement with more complex equations. Follow your institution’s policy.

Do I need to switch to metric?

No. Enter values in inches and pounds if preferred; the tool converts to centimeters and kilograms internally.

Is this calculator suitable for pediatrics?

Yes; Haycock and Mosteller are commonly cited for children. Always apply pediatric dosing protocols and clinical judgment.

Can I use BSA for chemotherapy dosing?

Many protocols are BSA-based, but dosing must be individualized. Use this tool as a reference only and always confirm dosing using official guidelines.

How accurate is BSA?

All equations are estimates derived from populations. Individual variability means that BSA should be one of several clinical considerations.

Why do different formulas yield slightly different results?

Each equation was derived from different datasets and modeling approaches; differences of a few percent are expected.

Why this BSA calculator is different

- Multiple peer‑reviewed formulas with instant side‑by‑side comparison - Mobile‑first design, fully keyboard navigable, WCAG 2.1 AA compliant - Live URL sharing of inputs for reproducible results - Clear validation, tooltips, and clinical‑grade rounding controls - No tracking, no external assets — optimized for Core Web Vitals

Always consult official clinical references and your institution’s policies before using BSA in decision‑making.

Tool developed by Ugo Candido. Content verified by CalcDomain Editorial Team. Last reviewed for accuracy on: September 14, 2025.