Body size

Body Surface Area (Mosteller & Du Bois)

Calculates body surface area using the Mosteller equation (UK standard) with the Du Bois equation for comparison.

Enter the required values to see the result.

Formula

\text{BSA} = \sqrt{\frac{\text{height (cm)} \times \text{weight (kg)}}{3600}} \qquad \text{BSA}_{Du\,Bois} = 0.007184 \times \text{height}^{0.725} \times \text{weight}^{0.425}

Caveats & limitations

All BSA equations derive from small historical samples and are imprecise at extremes of body habitus.
For chemotherapy, dose capping and obesity adjustments are protocol-specific — do not improvise.

Evidence & UK guidance

Primary evidence

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987;317(17):1098.
PubMed DOI
Du Bois D, Du Bois EF. A formula to estimate the approximate surface area if height and weight be known. Arch Intern Med. 1916;17:863–871.

UK practice

Mosteller is the equation most commonly embedded in UK chemotherapy and paediatric dosing protocols. Some protocols cap BSA (commonly at 2.0 m²) or adjust for obesity — always follow the local protocol.

Formula and citations last verified: 2026-08-03

Related calculators

BMI

Calculates BMI with WHO weight categories, plus the healthy weight range for the given height.

IBW / AdjBW

Calculates Devine ideal body weight and, when actual weight is provided, adjusted body weight for dosing in obesity.

Schwartz eGFR

Estimates GFR in children aged 1–16 years from height and serum creatinine (revised 'bedside' Schwartz equation, 2009).