Body Surface Area (BSA) Calculator
Calculate body surface area (BSA) in square meters from height and weight, using the Mosteller and Du Bois formulas.
How It's Calculated
Formula
\text{Mosteller: } BSA = \sqrt{\frac{\text{height (cm)} \times \text{weight (kg)}}{3600}}
\text{Du Bois: } BSA = 0.007184 \times \text{height (cm)}^{0.725} \times \text{weight (kg)}^{0.425}Body surface area (BSA) estimates the total external surface area of the body from height and weight, in square meters. This calculator reports both of the two most widely used BSA formulas: Mosteller (1987), a simpler square-root formula, and Du Bois & Du Bois (1916), an older power-law formula still in routine clinical and pharmacology use (for example, normalizing renal function measurements or dosing certain medications). This is an estimate for general informational and educational purposes, based on a published formula — it is not a medical diagnosis, and it is not a substitute for individualized advice from a qualified healthcare provider. Neither equation is exact for any individual — both are population-derived approximations, and the two formulas will not produce identical results for the same height and weight. This calculator does not classify body size and does not average the two results, since the BRD-specified formula set reports them as two independent, verifiable outputs rather than a single blended number.
Worked Examples
180 cm, 80 kg
- Mosteller: sqrt((180 × 80) / 3600) = sqrt(4) = 2.00 m²
- Du Bois: 0.007184 × 180^0.725 × 80^0.425 ≈ 2.00 m²
170 cm, 70 kg
- Mosteller: sqrt((170 × 70) / 3600) ≈ 1.82 m²
- Du Bois: 0.007184 × 170^0.725 × 70^0.425 ≈ 1.81 m²
Frequently Asked Questions
Why do the Mosteller and Du Bois formulas give slightly different results?
They're two independently derived equations from different eras of anthropometric research, each fit to its own historical dataset. Neither is universally more correct — this calculator reports both rather than picking one or averaging them.
What is BSA used for?
BSA is commonly used in clinical and pharmacology settings to normalize measurements (such as kidney function) or to scale medication dosing relative to body size, rather than using weight alone.
Is this an exact measurement of my body surface area?
This is an estimate for general informational and educational purposes, based on a published formula — it is not a medical diagnosis, and it is not a substitute for individualized advice from a qualified healthcare provider. Both formulas are population-derived approximations from height and weight, not a direct physical measurement of your body.