Two BSA formulae side by side, because they disagree, and knowing by how much matters more than picking one blindly.
Two BSA formulae, not one
Mosteller and Du Bois return different values for the same person. Showing both makes the spread visible instead of hiding it behind a single confident-looking figure.
Units you already use
Enter inches and pounds or centimetres and kilograms. The converted values are shown too, so you can carry them into anything else you are doing.
Frequently asked questions
- What is the Mosteller formula for body surface area?
- BSA in square metres equals the square root of height in centimetres multiplied by mass in kilograms, divided by 3,600. It is the simplest of the accepted formulae and the easiest to check by hand.
- Why do Mosteller and Du Bois give different answers?
- They are different empirical fits to different reference populations. Differences of a few percent are normal. The calculator shows both rather than implying one is authoritative.
- Does this tool interpret BMI?
- No. It returns the number and stops there. It offers no category, threshold or interpretation, and nothing it reports is health guidance.