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Body Surface Area (BSA) Calculator

Parameters

Measurements

For adults and children aged 1 year and older. Not intended for neonates or infants younger than 1 year.

RequiredAllowed: 1–200 kg

RequiredAllowed: 40–250 cm

Clinical context

Uses the Mosteller formula to estimate body surface area from height and weight for patients aged 1 year and older.

What this calculator shows

Estimates body surface area (BSA) for adults and children aged 1 year and older. The result is displayed in square metres (m²) to two decimal places.

How it works

Mosteller formula: BSA (m²) = √[height (cm) × weight (kg) ÷ 3600]. Entered units are converted to centimetres and kilograms before calculation; the unrounded values are used and only the displayed result is rounded.

Use and limitations

Use the measured height and weight appropriate to the clinical context. This calculator excludes neonates and infants younger than 1 year and does not replace a neonatal or infant-specific method. When BSA is used in a clinical protocol, use the formula and rounding rules specified by that protocol and verify the entered height and weight.