Body Surface Area Calculator
Estimate body surface area from height and weight using the Mosteller formula.
Try an example
1.82 m²
About this calculator
How This Body Surface Area Calculator Works
Enter height and weight, and the calculator returns an estimate of total body surface area in square meters, using the Mosteller formula.
Worked Example
A person 170 cm tall weighing 70 kg has a body surface area of about 1.82 m² — close to the commonly cited "average adult" figure of roughly 1.7-1.9 m².
The Formula
BSA (m²) = √(Height(cm) × Weight(kg) ÷ 3600) — the Mosteller formula, valued for being simple to calculate by hand while remaining accurate enough for most practical uses. Other formulas exist (Du Bois, Haycock), which produce very similar results using slightly different coefficients.
Why Body Surface Area Matters
BSA is used clinically to dose certain medications (particularly chemotherapy drugs) more precisely than a flat dose or weight-based dose alone, since it correlates well with metabolic rate and organ function. It's also used to normalize measurements like cardiac output for meaningful comparison between people of different sizes. This calculator is for general reference — actual medical dosing should always come from a healthcare provider.
Worked example
At 170 cm and 70 kg, BSA = √(170 × 70 ÷ 3600) ≈ 1.82 m², using the Mosteller formula.
Frequently asked questions
What is body surface area used for?
It's most commonly used in medicine to calculate drug dosages (especially chemotherapy) and to assess metabolic and cardiac measurements, since these often scale more closely with BSA than with weight alone.
Why the Mosteller formula specifically?
Mosteller is simple and widely used in clinical practice; other formulas (DuBois, Haycock, Gehan-George) exist and can give slightly different results, but generally agree within a few percent.
Is this something I should use to dose medication myself?
No — dosing decisions should always be made by a healthcare provider using validated clinical tools, not a general calculator.