Body Surface Area Calculator
Estimate body surface area in m² from height and weight. Compare Mosteller, Du Bois and Haycock formulas using metric or imperial inputs.
Formula and sources updated · Data sources · 2View algorithm, constants and default inputs (JSON)
How the three formulas compare
How the three formulas compare
Swipe horizontally to see more
| Formula | Body surface area | Difference from selected formula |
|---|---|---|
| Mosteller | 1.845m² | 0.00% |
| Du Bois | 1.848m² | 0.19% |
| Haycock | 1.847m² | 0.11% |
About this calculator
This calculator estimates body surface area from height and weight using the selected formula. Mosteller, Du Bois and Haycock can produce different estimates, so use the formula specified by a clinical protocol when one is required. This tool does not measure burn area or calculate medication doses. Units: cm / kg ↔ in / lb.
Worked example
calculated with the default values below
Units cm / kg · Height 175 cm · Weight 70 kg · Formula used for the headline figure Mosteller Body surface area 1.845 m² · Mosteller formula 1.845 m² · Du Bois formula 1.848 m² · Haycock formula 1.847 m² · Formula Mosteller · Height 175 cm · Weight 70 kg
Method and assumptions
Metric inputs use centimetres and kilograms. Imperial height is multiplied by 2.54 and weight by 0.45359237 before all three equations are calculated. The formula selector controls the headline BSA; the other estimates remain available for comparison. The comparison table reports 100 × (other estimate − selected estimate) / selected estimate. Values are displayed in square metres and rounded to three decimals, so displayed agreement is not proof that the underlying estimates are identical. The field bounds are input limits, not clinical reference intervals or proof of formula validity for every accepted body size.
Data sources
Disclaimer
These calculators are for general information only and are not a medical device, a diagnosis or a treatment plan. Reference ranges describe populations, not individuals, and do not account for pregnancy, medication, disability or athletic training. Discuss your own situation with a qualified healthcare professional.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
BSA = √(h·w/3600) [Mosteller]; 0.007184·h^0.725·w^0.425 [DuBois]; 0.024265·h^0.3964·w^0.5378 [Haycock]
- h
- Height (cm)
- w
- Weight (kg)
- BSA
- Body surface area (m²)
This calculator estimates body surface area from height and weight using the selected formula. Mosteller, Du Bois and Haycock can produce different estimates, so use the formula specified by a clinical protocol when one is required. This tool does not measure burn area or calculate medication doses. Units: cm / kg ↔ in / lb.
Frequently asked questions
Why does the same person get different values on different sites?
Different equations can return different estimates from the same height and weight. This calculator offers Mosteller, Du Bois and Haycock; the selected equation controls the primary result. If a clinical protocol requires a particular formula, use that formula. This page does not recommend or calculate a medication dose.
What can body surface area estimates be used for?
Body surface area can be an input to some clinical indices and dosing protocols. This calculator reports Mosteller, Du Bois and Haycock estimates from height and weight and lets you select which value is primary. These equations are estimates; a clinical protocol should specify its required formula. The tool does not calculate burn area or a medication dose.
Which height and weight units should I use for BSA?
Choose metric (cm and kg) or imperial (in and lb), then select the formula. Imperial inputs are converted to cm and kg before calculation; BSA is shown in m². With Mosteller, 180 cm and 80 kg gives 2 m². This is not a drug-dose calculator.