Body Surface Area Calculator

Body Surface Area (BSA) is the measured or estimated total surface of a human body. It's critical in clinical medicine — particularly for chemotherapy dosing, burn treatment, cardiac output calculations, and pediatric drug dosing where weight-based dosing is insufficient.

How to Use This Calculator

1. Enter your height (in cm or inches).
2. Enter your weight (in kg or lbs).
3. Select the formula: Mosteller (simplest), DuBois & DuBois (oldest), Haycock (best for children), or Boyd.
4. Click Calculate to see your BSA in square meters (m²).

BSA Formulas

Mosteller (1987): BSA = √(Height(cm) × Weight(kg) / 3600)

DuBois & DuBois (1916): BSA = 0.007184 × H^0.725 × W^0.425

Haycock (1978): BSA = 0.024265 × H^0.3964 × W^0.5378

Boyd (1935): BSA = 0.0003207 × H^0.3 × W^(0.7285 − 0.0188 × log(W))

Example Calculation

Height: 170 cm | Weight: 70 kg

• Mosteller: √(170 × 70 / 3600) = √3.306 ≈ 1.82 m²
• DuBois: 0.007184 × 170^0.725 × 70^0.425 ≈ 1.83 m²

Average adult BSA: 1.7–1.9 m² (women slightly less than men).

Clinical Uses of BSA

• Chemotherapy dosing: Most chemo drugs are dosed in mg/m² of BSA to standardize across body sizes.
• Burn treatment: Rule of Nines estimates % BSA burned for fluid resuscitation.
• Cardiac index: Cardiac output normalized to BSA for heart function assessment.
• Renal dosing: Adjustment of drug doses in kidney disease patients.

Frequently Asked Questions

Why is BSA preferred over weight for chemo dosing?

BSA correlates better with glomerular filtration rate and clearance of cytotoxic drugs than weight alone. It accounts for variation in body composition and provides more consistent pharmacokinetics across patients.

Which formula should I use?

For adults: Mosteller is widely used due to its simplicity and reasonable accuracy. DuBois is the historical standard. Haycock is preferred for pediatric patients. Your physician or pharmacist will specify which formula is used in their protocols.

Conclusion

Body surface area is a specialized clinical metric used primarily in medical dosing calculations. Use this calculator to quickly obtain BSA for educational or clinical planning purposes — always verify with your healthcare provider for actual treatment decisions.

Related: BMI Calculator | Lean Body Mass Calculator | Ideal Weight Calculator