How to use it
- Enter your Height in centimetres.
- Enter your Weight in kilograms.
- Read Body surface area, Du Bois formula in the result.
- Compare the five formulas in the table under All five formulas side by side.
How the formulas work
Body surface area (BSA) is the outer area of the body, in square metres. Doses and some measurements are scaled to it: chemotherapy is often dosed by BSA, and kidney clearance is often reported per 1.73 m² (Wikipedia, Body surface area). Each formula below estimates BSA from height and weight alone, and each was fitted to different measured people.
Du Bois and Du Bois (1916) is the most widely used formula. Mosteller (1987) proposed the square root of height times weight over 3,600 as a simpler calculation. Haycock and colleagues (1978) fitted their formula to measured subjects from premature infants to adults. Gehan and George (1970) and Boyd (1935) published the other two.
These figures are estimates for information, not medical advice: a prescriber sets any dose, and may use a measured value or a different formula.
Du Bois: BSA = 0.007184 x W^0.425 x H^0.725
Mosteller: BSA = square root of (H x W / 3600)
Haycock: BSA = 0.024265 x W^0.5378 x H^0.3964
Gehan and George: BSA = 0.0235 x W^0.51456 x H^0.42246
Boyd: BSA = 0.0333 x W^(0.6157 - 0.0188 x log10 W) x H^0.3
W is weight in kg, H is height in cm, and BSA is in m².Which formula should I use?
For most adults the five formulas agree to within a few hundredths of a square metre, so the choice matters less than the use of the number. The gap grows at the extremes of size. Haycock and colleagues (1978) reported that the Du Bois formula underestimated the area below 0.7 m², most strongly in newborns.
Use the formula your clinic or treatment protocol names. A dose that depends on BSA is set by the team treating you, and they may use a measured value instead of a formula.
What this calculator does not include
- A measurement. The formulas estimate BSA from height and weight, and a measured body surface area can differ.
- Body composition. BSA is less affected by excess fat than body weight is, but these formulas do not use body fat.
- Medicine doses. The page gives no dose; a prescriber decides it.
Worked example: 165 cm and 65 kg
Du Bois: 0.007184 x 65^0.425 x 165^0.725 = 1.72 m².
Mosteller: square root of (165 x 65 / 3600) = square root of 2.979 = 1.73 m².
| Formula | Body surface area |
|---|---|
| Mosteller | 1.73 m² |
| Du Bois | 1.72 m² |
| Haycock | 1.73 m² |
| Gehan and George | 1.74 m² |
| Boyd | 1.75 m² |
Frequently asked questions
Which body surface area formula is the most accurate?
No single formula is best for everyone. Du Bois and Mosteller are the two most often used, and for most adults they give almost the same figure. The choice usually follows the protocol of the clinic or team.
Why do the five formulas give different results?
Each formula was fitted to different groups of people and measurements, with its own powers of height and weight. The results are close for most adults and differ more for very small and very large people.
Is Mosteller's formula the same as the square root of height times weight over 3600?
Yes. Mosteller (1987) gave the simple form: the square root of height in centimetres times weight in kilograms, divided by 3,600.
Why is body surface area used for medicine doses?
Chemotherapy is often dosed according to BSA, and kidney clearance is often reported per 1.73 m². BSA is less affected by excess fat than body weight is (Wikipedia, Body surface area). The team treating you sets the dose.
Does this calculator store the numbers I enter?
No. The calculation runs in your browser and nothing you enter is sent to us.
Sources
- Du Bois D, Du Bois EF (1916): A formula to estimate the approximate surface area if height and weight be known, Arch Intern Med 17:863-871 (original paper, Zenodo)
- Mosteller RD (1987): Simplified calculation of body-surface area, N Engl J Med 317:1098 (PubMed)
- Haycock GB et al. (1978): Geometric method for measuring body surface area, J Pediatr 93:62-66 (PubMed)
- Gehan EA, George SL (1970): Estimation of human body surface area from height and weight, Cancer Chemother Rep 54:225-235 (PubMed)
- Body surface area, with the Boyd (1935) formula and the other four (Wikipedia)
Figures and text last checked on Tuesday, November 10, 2026.