Body composition calculator
Body surface area calculator
Get your body surface area in square metres from your height and weight (Mosteller). Free, instant, no sign-up.
Curious what your numbers mean? The coach explains and builds a plan.
What is body surface area?
Body surface area (BSA) is the total area of the outside of your body, in square metres. It's used in clinical settings to size drug doses and to index metabolic rate, because it scales with body size better than weight alone.
How this calculator works
We use the Mosteller formula — the simplest accurate estimate: BSA = √(height_cm × weight_kg / 3600). A 180 cm, 80 kg adult comes out to almost exactly 2.0 m².
What to do with it
BSA isn't a training metric on its own, but it's a useful reference when normalising other measures by body size. Want help making sense of your body-composition numbers and turning them into a plan? That's what the coach is for.