Your body surface area
The clinical sizing number — Du Bois and Mosteller, side by side.
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What BSA is used for
Body surface area estimates the total external area of your body in square metres. It tracks metabolic and physiological scale better than weight alone.
Clinically it is used to size drug doses (notably chemotherapy), cardiac index and renal function. The Du Bois formula is the historical standard; Mosteller is a simpler square-root form that agrees closely.
This is an estimate from height and weight, not a measured value, and is not a substitute for clinical dosing decisions.
Common questions
Which BSA formula should I use?
Du Bois is the traditional reference; Mosteller is easier to compute and within ~1–2% for most adults. We show both.
What is an average BSA?
Roughly 1.7 m² for adults (≈1.9 m² men, ≈1.6 m² women), but it scales widely with size.
Is BSA used for medication?
Yes — some drugs, especially chemotherapy, are dosed per m² of BSA. Always follow clinical guidance, not a web tool.
Is my data stored?
No. Everything is calculated in your browser. Nothing is sent to a server or saved.
Sources & references
- Mifflin MD, St Jeor ST, et al. “A new predictive equation for resting energy expenditure in healthy individuals.” Am J Clin Nutr. 1990;51(2):241–247.
- Frankenfield D, Roth-Yousey L, Compher C. “Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults.” J Am Diet Assoc. 2005;105(5):775–789.
This calculator provides estimates for general educational use and is not medical advice. Consult a qualified professional before making significant dietary changes.