THE NUMORIX GUIDE
How to use the BSA Calculator
Last reviewed September 14, 2026
What this calculator does
The calculator reports three empirical body-surface-area estimates in square meters: Mosteller = sqrt(weight * height / 3600), DuBois = 0.
Formula and method
The calculator reports three empirical body-surface-area estimates in square meters: Mosteller = sqrt(weight * height / 3600), DuBois = 0.007184 * weight^0.425 * height^0.725, and Haycock = 0.024265 * weight^0.5378 * height^0.3964. Weight must be in kg and height in cm for these formulas.
Variables and inputs
The UI accepts weight in kilograms and height in centimeters. It returns Mosteller, DuBois, and Haycock results rounded to four decimals, with no age, sex, body-shape, or clinical-use selector.
Worked example
For 70 kg and 170 cm: Mosteller = sqrt((70 * 170) / 3600) = 1.8181 m2; DuBois = 0.007184 * 70^0.425 * 170^0.725 = 1.8097 m2; Haycock = 0.024265 * 70^0.5378 * 170^0.3964 = 1.8257 m2.
How to interpret the result
The small differences show that BSA is formula-dependent. The outputs are estimated surface-area indices, not a direct measurement of skin area. A clinical team should use the formula specified by the drug label, protocol, or institution when BSA affects dosing or another decision.
Common mistakes to avoid
Convert pounds to kilograms and inches to centimeters before entering values. Do not average the three estimates automatically, and never turn a BSA value into a medication dose without the prescribed drug, regimen, and professional instructions.
Assumptions and limitations
BSA equations are population-derived approximations and can differ more at extremes of height, weight, age, or body composition. The engine does not validate inputs, select a clinically preferred formula, or account for treatment-specific dosing rules. This page is not a chemotherapy or medication dosing authority.