Body Surface Area Calculator
Calculate body surface area (BSA) from height and weight, using the Mosteller formula.
How to use the body surface area calculator
- Enter your height in centimeters.
- Enter your weight in kilograms.
- Body surface area (BSA) updates automatically, in square meters.
What is body surface area (BSA)?
Body surface area (BSA) is an estimate of the total skin area of your body, measured in square meters. This calculator uses the Mosteller formula — a simple and widely used approximation: BSA = √(height in cm × weight in kg / 3600). An average adult has a body surface area of roughly 1.7–2.0 m².
Frequently asked questions
Why use body surface area instead of just weight or BMI?
Body surface area gives a better measure of the total "outer size" of the body than weight alone, since it accounts for both height and weight together. In medicine, it's therefore used for certain dosing calculations where surface area is more relevant than body mass.
What is the Mosteller formula?
The Mosteller formula is a simple, widely used formula for estimating body surface area, published by Dr. R.D. Mosteller in 1987. It's easier to calculate by hand than older, more complex formulas (like the DuBois formula), and gives very similar results in practice.
What is a normal body surface area for an adult?
Most adults have a body surface area between 1.5 and 2.2 m², depending on height and weight — an average value often used as a reference is around 1.73 m².