🧍 Body Surface Area Calculator
Body surface area is used in medicine for some drug doses and to index heart and kidney measurements. This calculator uses the simple Mosteller formula.
Body surface area
How the Body Surface Area Calculator works
Height in centimeters is multiplied by weight in kilograms, divided by 3,600, and the square root is taken.
BSA (m²) = √(height(cm) × weight(kg) ÷ 3,600)
Step-by-step calculation
- 1Enter height and weight.
- 2Multiply cm × kg ÷ 3,600.
- 3Take the square root.
Worked example
Someone 180 cm tall weighing 80 kg: BSA = √(180 × 80 ÷ 3,600) = √4 = 2.00 m².
Body Surface Area Calculator examples
| Weight | Body surface area |
|---|---|
| 40 | 1.41 m² |
| 60 | 1.73 m² |
| 80 | 2.00 m² |
| 100 | 2.24 m² |
| 120 | 2.45 m² |
Other inputs kept at the calculator's default values. Results calculated by this calculator.
Why use a Body Surface Area Calculator?
Used in medicine to scale some doses and measurements.
Important factors that can affect your results
- Different BSA formulas give slightly different results.
- Accurate height and weight.
- Never use it to dose medicine yourself.
Frequently asked questions
What is a typical BSA?
Average adult values are often quoted around 1.7–1.9 m², higher for taller and heavier people.
Should I use this for medication doses?
No. Doses must always be worked out by a doctor or pharmacist.
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Last reviewed November 2026 · How we build and check our tools · Report a problem