Body Surface Area Calculator

Estimate body surface area from weight and height with the Mosteller, Du Bois, Haycock and Gehan and George formulas, side by side, in metric or imperial units.

Result

Estimate

Body surface area, Mosteller (1987)

1.84m²

Weight and height used: 70.0 kg, 175.0 cm

By each formula
Formula	BSA (m²)	Expression
Mosteller (1987)	1.845	√(height × weight / 3600), the simplest and most widely used
Du Bois and Du Bois (1916)	1.848	0.007184 × W^0.425 × H^0.725, the classic
Haycock (1978)	1.847	0.024265 × W^0.5378 × H^0.3964, fitted on children as well as adults
Gehan and George (1970)	1.854	0.0235 × W^0.51456 × H^0.42246, fitted on children

Note

Body surface area is an estimate from weight and height, used to scale doses and physiological quantities such as cardiac index. The formulas agree within a few percent for adults of ordinary build, and differ more for children and at extremes of size; use the one your protocol or institution specifies.

Note

Educational calculation. Do not use it to determine a drug dose without the checks your institution requires.

Significant figuresScientific notation

Calculation

√(height × weight / 3600), the simplest and most widely used, with weight in kg and height in cm

Formula

\text{Mosteller:}\quad \mathrm{BSA} = \sqrt{\dfrac{H\,(\mathrm{cm})\times W\,(\mathrm{kg})}{3600}}

\text{Du Bois:}\quad \mathrm{BSA} = 0.007184\;W^{0.425}\,H^{0.725}

\text{Haycock:}\quad \mathrm{BSA} = 0.024265\;W^{0.5378}\,H^{0.3964}

\text{Gehan and George:}\quad \mathrm{BSA} = 0.0235\;W^{0.51456}\,H^{0.42246}

$\mathrm{BSA}$: body surface area, in m²
$W$: weight, in kg
$H$: height, in cm

How it works

Body surface area is used to scale quantities that track the size of the body better than weight alone: cardiac output to a cardiac index, glomerular filtration rate, and some drug doses. It cannot be measured easily, so it is estimated from weight and height by formulas fitted to direct measurements.

The four formulas agree within a few percent for an adult of ordinary build and diverge more for children and at extremes of size. Haycock and Gehan and George were fitted on samples that include children, Du Bois and Du Bois on a small adult sample, and Mosteller is an algebraic simplification that agrees closely with the others. Use the formula your protocol or institution specifies.

Worked example

An adult weighs 70 kg and is 175 cm tall.

Mosteller: √(175 × 70 / 3600) = √3.4028 = 1.845 m².
Du Bois: 0.007184 × 70^0.425 × 175^0.725 = 1.848 m².

The BSA is about 1.85 m² by either formula. Haycock gives 1.847 and Gehan and George 1.854.

These are the values the calculator opens with, so you can check its output against this example.

Assumptions

Weight and height are measured, and the person is of typical build for the formula's sample.
The result is an estimate, not a measurement.

Common mistakes

Mixing formulas when comparing values, or when a protocol specifies one.
Entering weight in pounds or height in inches without selecting the unit.
Using a BSA-based dose without the checks the institution requires.

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Body Surface Area Calculator

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Calculation

Formula

How it works

Worked example

Assumptions

Common mistakes

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