Overview
Body surface area estimates the external skin area and is used in physiology and some clinical assessments. Formulas differ slightly, so this tool shows more than one estimate rather than a single number.
Formula
The simple Mosteller formula is the square root of height in centimeters times weight in kilograms divided by 3600. The older Du Bois formula uses fractional exponents.
How it works
Enter height and weight
Choose metric or imperial units.
Compare both methods
The results are usually close; a small difference is normal.
Do not use it for dosing
Medication adjustment requires professional supervision and a clinical protocol.
Worked examples
170 cm and 70 kg
Mosteller is about 1.82 m² and Du Bois about 1.81 m².
160 cm and 60 kg
Mosteller is about 1.63 m² and Du Bois about 1.62 m².
Frequently asked questions
What is body surface area used for?
It is used in metabolism and organ-function studies and some clinical assessments, but it is not a measure of fat or fitness.
Why do the results differ?
The formulas were built from different populations and use different mathematics. A small difference is expected.
Can it be used for medication dosing?
No. This tool is educational and does not calculate doses. Many factors determine dosing, and self-estimation is unsafe.
Is it suitable for children?
Children have specific formulas; assessment should be left to a clinician.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.