Body surface area (BSA) calculator
Calculate body surface area in m² from height and weight, with the Mosteller, Du Bois, Haycock, Gehan-George and Boyd formulas.
Height and weight
The result appears as soon as height and weight are entered. It also works for children.
Height
Estimated body surface area
Mosteller
m²
Skin surface estimated from height and weight, used in medicine to adjust some doses and to normalise measurements such as cardiac output.
By formula
- MostellerReference1987, the most used, easy to work out
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- Du Bois1916, the historical formula
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- Haycock1978, also built from children
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- Gehan-George1970, based on more than 400 measurements
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- Boyd1935, accurate at extreme weights
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Method & sources
The Mosteller formula, recommended for its simplicity and accuracy, gives the main result. Du Bois, Haycock, Gehan-George and Boyd are shown for comparison; they usually differ by less than 5%.
Formula
Mosteller: BSA = √(height cm × weight kg ÷ 3600) · Du Bois: BSA = 0.007184 × height^0.725 × weight^0.425Limitations
- Body surface area is an estimate from height and weight, not a direct measurement of the skin.
- The formulas diverge more for very young children and extreme builds.
- A body surface area result must never be the only basis for a treatment decision.