Body Surface Area Calculator
Calculate your body surface area (BSA), used in medicine for drug dosing and cardiac indices.
Reviewed October 7, 2026 Runs in your browser — inputs are never stored
This tool provides general educational estimates only and is not medical advice. It does not diagnose, treat, or replace guidance from a qualified healthcare provider. Consult a doctor for decisions about your health.
About the Body Surface Area Calculator
The body surface area calculator estimates the total surface area of the body in square metres. BSA is used in medicine to dose some drugs, including many chemotherapy agents, and to index measurements such as cardiac output. The tool uses the Mosteller formula — the square root of height in centimetres multiplied by weight in kilograms, divided by 3,600 — and also shows the older Du Bois estimate for comparison. An average adult has a BSA of roughly 1.7 to 2.0 m². Any dosing decision must be made by a qualified clinician.
How to use it
- 1Enter weight in kilograms.
- 2Enter height in centimetres.
- 3Press Calculate to see BSA by the Mosteller and Du Bois formulas.
Worked example
a person weighing 75 kg and 178 cm tall has a Mosteller BSA of √(178 × 75 ÷ 3,600) ≈ 1.93 m². The Du Bois formula gives almost the same value.
How it works
Mosteller formula
BSA = √(height(cm) × weight(kg) / 3600). We also show the Du Bois estimate.
Who it is for
Healthcare students, nurses and pharmacists checking BSA-based calculations.
Why it helps
BSA tracks metabolic size more closely than weight alone, which is why it is used for some drug dosing.
Common use cases
- Checking a BSA value used in a dosing calculation
- Learning how the Mosteller and Du Bois formulas compare
- Indexing physiological measurements to body size
Frequently asked questions
A:Many chemotherapy and medication doses are scaled to body surface area rather than weight alone.
A:Mosteller is simple and widely used; Du Bois is a classic alternative.
Reviewed for accuracy · Last updated October 7, 2026
Formulas follow recognised clinical references — including WHO BMI classifications, the Mifflin-St Jeor equation, and Naegele’s rule — and are periodically checked against published reference values.
CalcWisee Editorial Team
Calculator development and formula review
CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.
Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards
References & sources
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