Body Surface Area (BSA) Calculator
Estimate your body surface area using the Mosteller formula. Supports kg, lbs, cm, and feet.
How the Body Surface Area Calculator Works
Body surface area, or BSA, is the total external surface of the human body. It is used in health, medicine, and fitness to estimate values such as drug dosage, metabolic rate, caloric needs, and physiological scaling. BSA is considered more accurate than weight alone when calculating dosage or evaluating the effect of medication.
This tool uses the Mosteller formula, one of the most widely accepted and simplest BSA equations. It calculates BSA by multiplying a person's height in centimetres by weight in kilograms, dividing the result by 3600, and then taking the square root of that value. The formula is:
BSA = √(height(cm) × weight(kg) / 3600)
The calculator converts units automatically if you enter height in feet and inches or weight in pounds. Everything is processed instantly on your device for privacy and speed.
BSA is often used in combination with BMI, LBM, body fat percentage, BMR, and TDEE calculators for training plans, nutrition analysis, and medical reference.
Frequently Asked Questions
What is body surface area?
Body surface area is a measurement of the total external area of the human body.
Which formula does this calculator use?
This tool uses the Mosteller formula, which is simple, widely used, and supported in medical settings.
Can I enter height in feet and inches?
Yes. The calculator converts feet and inches to centimetres automatically.
Is my information saved or sent anywhere?
No. All calculations occur locally in your browser only.