Body Surface Area Calculator (Mosteller)
Enter your weight and height to get your body surface area in m².
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Formula
BSA (m²) = √(height (cm) × weight (kg) ÷ 3600)
Worked example
175 cm and 70 kg: 175 × 70 = 12,250; 12,250 ÷ 3600 = 3.4028; the square root is 1.84 m².
Frequently asked questions
What is body surface area?
Body surface area (BSA) is the total outer surface of the body in square metres. Clinicians use it to scale drug doses and to index measures such as cardiac output. An average adult is about 1.7 to 1.9 m².
What is the Mosteller formula?
BSA = square root of (height in cm x weight in kg ÷ 3600). For 175 cm and 70 kg that is the square root of 3.4028, which is 1.84 m².
Why is Mosteller used instead of other formulas?
It is simple enough to do on a calculator and gives results close to the Du Bois and Haycock formulas for adults. At 180 cm and 80 kg it gives exactly 2.00 m².
Can I use this to work out a medication dose?
The number can feed a dose calculation, but doses must be set by a prescriber. Use this only to understand the figure, not to decide treatment.