Body Surface Area Calculator: Mosteller, Du Bois, BSA
Estimate body surface area in square metres from weight and height with the Mosteller, Du Bois, Haycock, Gehan and George, and Boyd formulas side by side, in metric or US units. Nothing is uploaded.
Enter a weight and height to see the body surface area.
About the Body Surface Area Calculator
The Body Surface Area Calculator estimates the total surface area of the human body, in square metres, from weight and height. Body surface area, or BSA, is used in medicine to scale drug doses, especially in cancer chemotherapy, to index cardiac output and kidney function, and to estimate fluid needs after burns. It tracks metabolic size better than weight alone. Enter a weight and a height in metric or US customary units and the calculator shows five published formulas side by side: Mosteller, Du Bois and Du Bois, Haycock, Gehan and George, and Boyd.
This is an estimate, not medical advice. Never use it on its own to dose a medicine: doses are set and checked by a doctor or pharmacist, who also decide which formula and which weight to use.
How to use it
Steps
- Choose metric (kilograms and centimetres) or US customary units (pounds and inches).
- Enter the weight and the height.
- Read the five estimates. Mosteller is shown first because it is the most widely used.
Which formula
For adults of ordinary build the five formulas agree within a few hundredths of a square metre. Mosteller is simple and common in oncology. Du Bois and Du Bois is the oldest and was fitted to only nine people, so it tends to underestimate in infants and in larger adults. Haycock and Gehan and George were fitted to larger groups including children. Boyd, which uses weight in grams with a logarithmic exponent, is often quoted for infants.
The formulas
With weight W in kilograms (G in grams for Boyd) and height H in centimetres, each result in square metres:
Worked example
For a person who weighs 70 kg and is 170 cm tall, Mosteller gives 1.82 m², Du Bois 1.81 m², Haycock 1.83 m², Gehan and George 1.83 m² and Boyd 1.83 m². The same person entered as 154.3 lb and 66.9 in gets the same answers.
Privacy
Nothing is uploaded: every calculation runs in your browser and your measurements never leave your device.
Related tools
Estimate lean mass with the Lean Body Mass Calculator, check body mass index with the BMI Calculator, or convert centimetres to inches with the Length Converter and kilograms to pounds with the Mass Converter.
Sources
- Mosteller R.D. Simplified calculation of body-surface area. New England Journal of Medicine 1987; 317: 1098.
- Du Bois D., Du Bois E.F. A formula to estimate the approximate surface area if height and weight be known. Archives of Internal Medicine 1916; 17: 863–871.
- Haycock G.B., Schwartz G.J., Wisotsky D.H. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. Journal of Pediatrics 1978; 93: 62–66.
- Gehan E.A., George S.L. Estimation of human body surface area from height and weight. Cancer Chemotherapy Reports 1970; 54: 225–235.
- Boyd E. The Growth of the Surface Area of the Human Body. University of Minnesota Press, Minneapolis, 1935.
Open-source credits
The calculations are implemented in-house in TypeScript, with no third-party library. They follow the published Mosteller, Du Bois and Du Bois, Haycock, Gehan and George, and Boyd body surface area formulas listed above.
Frequently asked questions
What is body surface area used for?
Body surface area is used to scale the doses of many chemotherapy drugs, to index measurements such as cardiac output and kidney function to body size, and to estimate fluid needs after burns. It reflects metabolic size better than weight alone.
Which body surface area formula is best?
For most adults the formulas agree within a few hundredths of a square metre, so the choice rarely matters. Mosteller is the most widely used because it is simple. Hospitals and drug protocols usually name the formula to use, and that choice should be followed.
What is an average body surface area?
An average adult has a body surface area of roughly 1.7 to 2.0 square metres; men are usually larger than women. A newborn has about 0.25 square metres. A person who weighs 70 kg and is 170 cm tall has about 1.82 square metres by the Mosteller formula.
Can I use this to calculate a drug dose?
No. This calculator is an estimate, not medical advice. Drug doses depend on more than body surface area, including kidney and liver function and the protocol in use, and are always set and checked by a doctor or pharmacist.