Body Surface Area Calculator

Calculate your body surface area from your height and weight using the Mosteller formula. See the result in square metres, square feet and square inches.

Choose your unit system, then enter your height in cm (metric) or feet & inches (imperial) and your weight in kg (metric) or pounds (imperial). The calculator applies the Mosteller formula and shows the area in square metres, feet and inches.

Body surface area
In square feet
In square inches

A body surface area (BSA) calculator estimates the total surface area of your body from height and weight. BSA is used for drug dosing, cardiac output and burn assessment more accurately than weight alone.

The maths (Mosteller)

BSA (m²) = √(height (cm) × weight (kg) ÷ 3600)

Convert to square feet (×10.764) or square inches (×1550). Mosteller is the most widely used BSA formula for its simplicity and accuracy.

Examples

  • 178 cm, 80 kg = ~1.98 m²
  • About 21.3 ft² or 3,069 in²
  • Taller or heavier people have a larger surface area

Frequently asked questions

Why use BSA instead of weight?

Many drug doses and physiological measures scale better with surface area than body weight, especially across different body sizes, so BSA gives safer and more consistent results.

Is Mosteller the only formula?

No — Du Bois, Haycock and Gehan-George exist too. Mosteller is popular because it's simple and agrees closely with the others for most adults.

Just for the giggles, much love.
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