Body Surface Area Calculator
Compute BSA using Du Bois, Mosteller, Haycock and Gehan-George clinical formulas.
Inputs
Mosteller (1987)
1.9365m²
Most commonly used in drug dosing protocols.
Du Bois & Du Bois (1916)
1.9424m²
Haycock et al. (1978)
1.9381m²
Preferred for children and extreme body habitus.
Gehan & George (1970)
1.9438m²
Average (all four)
1.9402m²
Step by step
Mosteller
√(180 × 75 / 3600)
= 1.9365 m²
Du Bois
0.007184 × 75^0.425 × 180^0.725
= 1.9424 m²
Haycock
0.024265 × 75^0.5378 × 180^0.3964
= 1.9381 m²
Gehan-George
0.0235 × 75^0.51456 × 180^0.42246
= 1.9438 m²
How it works
Body Surface Area is used in oncology (chemotherapy dosing), cardiology (cardiac output normalisation), burn management (fluid resuscitation), and nephrology (GFR expression). The Mosteller formula is favoured in clinical practice because its form is simple enough to compute mentally or with a basic calculator. DEXA and 3D scanning give more accurate BSA, but formula-based estimates are adequate for most clinical dosing purposes.
Formulas
Mosteller
BSA = √(Height(cm) × Weight(kg) / 3600)
- H
- Height in cm
- W
- Weight in kg
Du Bois
BSA = 0.007184 × Weight^0.425 × Height^0.725
- H
- Height in cm
- W
- Weight in kg
Haycock
BSA = 0.024265 × Weight^0.5378 × Height^0.3964
- H
- Height in cm
- W
- Weight in kg
Gehan-George
BSA = 0.0235 × Weight^0.51456 × Height^0.42246
- H
- Height in cm
- W
- Weight in kg
BSA calculations are estimates for informational and educational purposes. Drug dosing, cardiac output normalisation, and burn fluid resuscitation must be performed by qualified healthcare professionals using validated clinical protocols. This tool is not a substitute for medical advice.
Frequently Asked Questions
Why are there multiple formulas?
Each formula was derived from a different patient population. Du Bois (1916) used nine healthy adults; Mosteller (1987) approximated several earlier formulas for clinical convenience; Haycock (1978) validated across infants to adults; Gehan & George (1970) used a large cross-sectional sample. For most adults in normal weight range they agree within 2–3%.
Which formula should I use for drug dosing?
Follow your pharmacy protocol. Mosteller is most widely used in modern oncology (e.g. ASCO BSA guidelines). Du Bois remains common in nephrology. Haycock is preferred for paediatric dosing.
What is a normal BSA for an adult?
The conventional reference BSA used in cardiac output normalisation is 1.73 m² (derived from the Du Bois formula for an average adult). In practice, typical adults range from 1.6 to 2.1 m², with men averaging about 1.9 m² and women about 1.7 m².