Body Surface Area Calculator
Calculate your body surface area in square meters using the Mosteller formula.
cm
kg
- 1
Height × Weight
175 × 70 = 12,250 - 2
Divide by 3600
12,250 ÷ 3600 = 3.402778 - 3
Body surface area
√3.402778 = 1.84Mosteller formula: √(height × weight ÷ 3600) gives BSA in m².
Formula
How this is calculated
This tool estimates body surface area using the Mosteller formula, which takes two inputs: height in centimetres and weight in kilograms. It multiplies the two numbers together, divides the product by 3600, and then takes the square root of that result. The 3600 is a fixed scaling constant (60 × 60) chosen so the answer comes out in square metres (m²); it is not derived from your measurements.
Because the formula uses a single empirical equation rather than measuring you directly, it is a statistical estimate calibrated on population data, not an exact measurement of your skin. It assumes typical adult body proportions, so it loses accuracy at the extremes — very tall, very short, very lean, or very obese bodies, and small children whose proportions differ from adults.
The square-feet figure is just the m² value multiplied by 10.7639. Most healthy adults land between roughly 1.5 and 2.0 m². Different equations (Du Bois, Haycock) give slightly different numbers, so for clinical dosing always follow your protocol's required method.
Examples
| Input | Result |
|---|---|
| 175 cm, 70 kg | BSA ≈ 1.84 m² |
About this calculator
Body surface area (BSA) estimates the total external area of the human body and is widely used in medicine, particularly for calculating drug dosages, chemotherapy regimens, and indexing measures like cardiac output. The Mosteller formula is the most popular method because it is simple, fast to compute, and accurate across a broad range of body sizes.
Because BSA reflects both height and weight, it often scales physiologic quantities better than weight alone. A typical adult BSA is around 1.6 to 2.0 m². Different formulas (Du Bois, Haycock, and others) can give slightly different results, so for clinical use always follow the specific method your protocol requires.
Frequently asked questions
Many physiologic functions scale more closely with surface area than body weight, so BSA can give a more consistent dose across patient sizes.
Mosteller is simpler and yields results very close to the older Du Bois formula across most body sizes, which is why it is widely preferred.
A typical adult value is roughly 1.7 m², with most adults falling between about 1.5 and 2.0 m².
Also known as
TG we-Calculate Editorial Team. (2026). Body Surface Area Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/body-surface-area-calculator
TG we-Calculate Editorial Team. "Body Surface Area Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/body-surface-area-calculator.
TG we-Calculate Editorial Team, "Body Surface Area Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/body-surface-area-calculator
@misc{wecalculate_body_surface_area_calculator, title = {Body Surface Area Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/body-surface-area-calculator}}, year = {2026}, note = {TG we-Calculate} }
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