Body Surface Area Calculator
Calculate BSA using multiple medical formulas for drug dosing and clinical assessments.
Your Measurements
Primary Formula
Unit
Height
ft
in
Weight
lb
Your Body Surface Area
Body Surface Area (BSA)
—
m²
m²
Average adult: 1.7 m²
Du Bois
— m²
Mosteller
— m²
Haycock
— m²
Gehan-George
— m²
What is Body Surface Area?
Body Surface Area (BSA) is the measured or calculated surface area of a human body, expressed in square meters (m²). It’s more accurate than body weight alone for many physiological calculations.
Average adult BSA is approximately 1.7 m² for women and 1.9 m² for men. BSA correlates better with metabolic mass than body weight.
BSA Formulas Comparison
| Formula | Best For |
|---|---|
| Du Bois (1916) | Most widely used, standard reference |
| Mosteller (1987) | Simplified calculation, easy mental math |
| Haycock (1978) | Pediatric patients, children |
| Gehan-George (1970) | Research applications |
Most formulas give similar results for average adults. Differences become more significant at extreme heights or weights.
Medical Applications
- Chemotherapy dosing: Most cancer drugs are dosed based on BSA (mg/m²) for safer, more accurate administration.
- Cardiac index: Cardiac output divided by BSA gives the cardiac index, a key measure of heart function.
- Renal function: GFR (glomerular filtration rate) is often normalized to BSA for comparison between patients.
- Burn assessment: BSA helps estimate total body surface area affected by burns.
Important Considerations
- Estimates only: All BSA formulas are approximations derived from limited population studies.
- Obesity: Standard formulas may overestimate BSA in obese patients. Some clinicians use adjusted body weight.
- Children: Haycock formula is preferred for pediatric patients as it was developed with children’s data.
- Medical decisions: Always consult healthcare professionals for drug dosing. This calculator is for educational purposes.