Body Surface Area Calculator
Calculate body surface area from height and weight with the Mosteller and Du Bois formulas.
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How to do it
- 1Fill in the boxes
Type your numbers or pick the options you need.
- 2See the result
The answer updates right away as you change a value.
- 3Use it
Copy the result or note it down. Nothing is sent anywhere.
About this tool
Enter height in centimetres and weight in kilograms. The tool gives body surface area with the Mosteller formula, the one most often used in medicine, and with the Du Bois formula for comparison.
Where BSA is used
Doctors use body surface area to dose some medicines, especially in cancer care, and to index heart and kidney measures. The adult average is about 1.7 square metres.
Formulas
Mosteller: square root of height in cm times weight in kg divided by 3600. Du Bois: 0.007184 × weight^0.425 × height^0.725.
Disclaimer
This is general information. Doses must be set by a clinician.
Tips for best results
Check every box before you rely on a result, because one wrong digit changes the whole answer. Use the exact figures from your payslip, bill, certificate or contract, and keep a note of the date you calculated. Rates, thresholds and rules change from time to time, so for tax, fees and legal matters treat the output as an estimate and confirm with the official source named on this page. You can run as many scenarios as you like; nothing is saved or sent, and refreshing the page clears the boxes.
Quick facts
- Category: Everyday Tools
- Works in your browser, no sign-up, no upload.
- Your input stays on your device.
- Available in English.
- Content last reviewed:
Frequently asked questions
Which formula is better?
Mosteller is simple and common. Results differ very little.
What is a normal BSA?
About 1.7 m² for adults.
Can I use it for children?
The formulas work, but doses for children must come from a doctor.
Is it medical advice?
No.