Body Surface Area Calculator
This calculator is for informational purposes only and is not a substitute for professional medical advice. Consult a healthcare provider for personal health decisions.
All formulas
| Formula | BSA |
|---|---|
| Du Bois | 1.809708 m² |
| Mosteller | 1.818119 m² |
| Haycock | 1.825677 m² |
| Boyd | 0.028535 m² |
BSA from height and weight (Du Bois, Mosteller, Haycock, Boyd)
How Body Surface Area Is Calculated
Body surface area (BSA) estimates total skin surface in square meters. Clinicians use BSA to scale drug doses (especially chemotherapy), cardiac index, and metabolic calculations where weight alone misrepresents size. BSA correlates better than body weight with physiological processes distributed across surface area.
The Du Bois formula (1916) remains common: BSA = 0.007184 × height(cm)^0.725 × weight(kg)^0.425. For 170 cm and 70 kg: BSA ≈ 1.81 m². The Mosteller formula simplifies to √(height × weight / 3600) with height in cm and weight in kg — often within 1–2% of Du Bois.
Haycock and Boyd use alternate exponents; Boyd incorporates log₁₀(weight) for a weight-dependent exponent. Mosteller is easiest to compute mentally; Du Bois and Haycock appear frequently in medical literature. This calculator shows all four for comparison.
BSA equations were derived from height-weight datasets and may less accurately represent extreme obesity, very short stature, or unusual body composition. For pediatric dosing, specialized pediatric BSA charts are preferred. Always follow institutional protocols for medication dosing rather than relying solely on online calculators.
Examples
| Example | Result |
|---|---|
| 170 cm, 70 kg (Du Bois) | ≈ 1.81 m² |
| 180 cm, 80 kg | ≈ 2.0 m² |
| 160 cm, 55 kg | ≈ 1.58 m² |
Frequently asked questions
Many physiological processes scale with surface area. BSA reduces overdose risk in large patients and underdosing in small ones compared to weight-only scaling.
Institutional protocol determines the formula. Mosteller and Du Bois are most common; they usually agree within a few percent for typical adult sizes.
Most adults fall between 1.6 and 2.0 m² depending on height and weight. A 170 cm, 70 kg person is approximately 1.81 m² (Du Bois).