Weight, Height
Body Surface Area (BSA) Calculator
Calculate body surface area from height and weight.
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How this calculator works
Body surface area is the total area of the skin, expressed in square meters. Clinicians use it to scale chemotherapy doses, to index heart output and to estimate kidney function, because it tracks metabolic size better than weight alone. The Mosteller formula is the simplest and the most widely used today; the older Du Bois formula gives nearly the same result for most adults.
Formula
- Mosteller: BSA = √(height in cm × weight in kg / 3600)
- Du Bois: BSA = 0.007184 × weight^0.425 × height^0.725
Worked example
70 kg, 175 cm
- Weight
- 70 kg
- Height
- 175 cm
Result1.84 m²
Body surface area by the Mosteller formula for 70 kg and 175 cm.
Things to keep in mind
- Never calculate a medicine dose yourself from this result. Dosing must be done by the prescribing clinician.
- For general information only. It is not medical advice; talk to a health professional about your own situation.
Frequently asked questions
What is a normal body surface area?
About 1.9 m² for adult men and 1.6 m² for adult women. 1.73 m² is the conventional reference value used to standardize kidney function.
Which BSA formula should I use?
Mosteller is the usual choice because it is simple and agrees closely with the others. Hospitals may specify a formula in their protocols.
Why is BSA used instead of weight?
Many body functions, such as heart output and kidney filtration, scale more closely with surface area than with weight.
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Results are estimates based on the values you enter and the published method shown above. They do not replace professional medical, financial or legal advice. Method reviewed October 7, 2026. About this site