Body Surface Area Calculator · Practical guide
Normal BSA for Adults
Average adult BSA values, a quick lookup table, and what your square-meter number actually means.
At a glance
The Average Numbers
The average body surface area for adult men is about 1.9 m², and for adult women about 1.6 m². Those are population averages — your own value depends on your specific height and weight, and anything between roughly 1.4 and 2.2 m² is ordinary for adults.
Interactive tool
Body Surface Area Calculator
Enter your own values, then compare the result with the examples below.
Body Surface Area Results
BSA Lookup Table (Mosteller Formula)
| Build | Height | Weight | BSA |
|---|---|---|---|
| Petite woman | 155 cm | 50 kg | 1.47 m² |
| Average woman | 165 cm | 65 kg | 1.73 m² |
| Average adult | 175 cm | 70 kg | 1.85 m² |
| Average man | 180 cm | 80 kg | 2.00 m² |
| Tall, heavy man | 190 cm | 100 kg | 2.30 m² |
Computed with √(height × weight ÷ 3600). Enter your own numbers above for an exact result from all four major formulas.
Why There Is No Single "Normal"
Unlike blood pressure, BSA is a descriptive measurement, not a health metric — there is no unhealthy BSA. It simply scales with body size, which is exactly why medicine uses it: it lets drug doses, cardiac index, and kidney function benchmarks be expressed per square meter so they apply fairly to a 50 kg patient and a 100 kg patient alike.
Where Your BSA Number Gets Used
The most common use is chemotherapy and other narrow-margin drug dosing in mg/m². BSA also appears in cardiology (cardiac index = cardiac output ÷ BSA, normal about 2.5–4.0 L/min/m²), in burn assessment, and in renal medicine. Knowing your own value makes those figures on a treatment plan much easier to read.
Frequently Asked Questions
What is the average BSA for a woman?
About 1.6 m². A woman at 165 cm and 65 kg computes to roughly 1.72–1.73 m² depending on the formula, which is right in the typical adult female range.
What is the average BSA for a man?
About 1.9 m². A man at 180 cm and 80 kg lands at essentially 2.00 m² with the Mosteller formula, slightly above the population average.
Does BSA change as I gain or lose weight?
Yes. BSA is computed from current height and weight, so significant weight change shifts it. Clinicians often recalculate when weight moves by about 5 to 10 percent.
Is a higher or lower BSA healthier?
Neither. BSA reflects body size, not health — it exists to scale medical measurements to the individual, similar to how a shoe size describes your foot rather than judging it.