🧍 Body Surface Area Calculator

Calculate your Body Surface Area (BSA) in m² using three clinically validated formulas — Du Bois, Mosteller, and Haycock. BSA is widely used in medicine for drug dosing, burn assessment, and cardiac output calculations.

Height (cm)

Weight (kg)

BSA Formulas

Du Bois & Du Bois (1916) — Most widely used

BSA = 0.007184 × H^0.725 × W^0.425

Mosteller (1987) — Simplest formula

BSA = √(H × W / 3600)

Haycock (1978) — Preferred for pediatrics

BSA = 0.024265 × H^0.3964 × W^0.5378

Where H = height in cm, W = weight in kg. All formulas return BSA in m².

How to Use the BSA Calculator

1

Choose Your Unit System

Select Metric (cm / kg) or Imperial (ft + in / lbs). The calculator handles unit conversion automatically.
2

Enter Height

In metric, enter your height in centimetres. In imperial, enter feet and inches in the two separate fields.
3

Enter Weight

Enter your body weight in kilograms or pounds depending on the selected unit system.
4

View Your BSA

See BSA results from all three formulas and their average, plus a clinical interpretation of your result.

Example Calculation

A person who is 170 cm tall and weighs 70 kg:

Du Bois = 0.007184 × 170^0.725 × 70^0.425 = 1.78 m²

Mosteller = √(170 × 70 / 3600) = 1.77 m²

Haycock = 0.024265 × 170^0.3964 × 70^0.5378 = 1.78 m²

Average BSA = 1.78 m²

Medical Uses of BSA

BSA is preferred over weight alone for many clinical applications because it better accounts for differences in body size and composition:

•Chemotherapy dosing: Most cytotoxic drugs are dosed in mg/m² to standardise exposure across patients of different sizes, reducing toxicity risk.
•Burns assessment: The Rule of Nines uses BSA to estimate the percentage of body surface affected by burns, guiding fluid resuscitation.
•Cardiac output: Cardiac index (CI = cardiac output / BSA) normalises heart function measurements for patient size.
•Renal function: GFR is often expressed per 1.73 m² (average adult BSA) to allow comparison between individuals.

Note: This calculator is for informational purposes only. Always consult a healthcare professional for clinical dosing decisions.