Body Surface Area Calculator
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Results
Body surface area 1.88 m² (Mosteller) for 160 lb at 5 ft 9 in; the five formulas range from 1.88 to 1.89 m².
| Formula | Year | Equation | BSA (m²) | vs Mosteller |
|---|---|---|---|---|
| Mosteller | 1987 | √(H × W ÷ 3600) | 1.88 | – |
| Du Bois & Du Bois | 1916 | 0.007184 × W^0.425 × H^0.725 | 1.879 | −0% |
| Haycock | 1978 | 0.024265 × W^0.5378 × H^0.3964 | 1.884 | +0.2% |
| Gehan & George | 1970 | 0.0235 × W^0.51456 × H^0.42246 | 1.89 | +0.5% |
| Boyd | 1935 | 0.0003207 × H^0.3 × G^(0.7285 − 0.0188 × log₁₀G) | 1.888 | +0.5% |
Body surface area is used to dose some medicines and to scale lab results. Your care team chooses the formula and checks any dose; never adjust a medicine yourself from an online estimate.
This is an estimate from a published formula, not medical advice. Talk to a doctor or registered dietitian about your own situation.
How to use the body surface area calculator
- Enter height and weight in either unit system.
- Read the Mosteller BSA at the top, then the other four formulas and the spread between them.
- Use the comparison table to see each equation and how much it differs from Mosteller in percent.
Body surface area formulas
Du Bois & Du Bois (1916): BSA = 0.007184 × W^0.425 × H^0.725
Haycock (1978): BSA = 0.024265 × W^0.5378 × H^0.3964
Gehan & George (1970): BSA = 0.0235 × W^0.51456 × H^0.42246
Boyd (1935): BSA = 0.0003207 × H^0.3 × G^(0.7285 − 0.0188 × log₁₀G)
H = height (cm), W = weight (kg), G = weight (g), BSA in m²
Measuring the skin's surface directly is impractical, so these formulas were fitted to careful measurements of a small number of people. Delafield and Eugene Du Bois measured nine people in 1916. Edith Boyd fitted hers to hundreds of published measurements in 1935. Gehan and George refitted measurements from Boyd's collection in 1970, in a cancer chemotherapy journal, and Haycock, Schwartz and Wisotsky measured 81 people from premature babies to adults in 1978. Robert Mosteller's 1987 letter showed that a simple square root gives nearly the same answers, which is why it is now the most widely used.
Worked example
For someone 5 ft 9 in (175.3 cm) weighing 160 lb (72.6 kg), Mosteller gives √(175.3 × 72.6 ÷ 3600) = 1.88 m². The other formulas give Du Bois & Du Bois1.88, Haycock1.88, Gehan & George1.89, Boyd1.89 m², all within 0.6% of each other.
BSA by height and weight (Mosteller)
Generated with the calculator's engine, in m².
| Height | 50 kg (110 lb) | 60 kg (132 lb) | 70 kg (154 lb) | 80 kg (176 lb) | 90 kg (198 lb) | 100 kg (220 lb) | 110 kg (243 lb) |
|---|---|---|---|---|---|---|---|
| 150 cm | 1.44 | 1.58 | 1.71 | 1.83 | 1.94 | 2.04 | 2.14 |
| 160 cm | 1.49 | 1.63 | 1.76 | 1.89 | 2 | 2.11 | 2.21 |
| 170 cm | 1.54 | 1.68 | 1.82 | 1.94 | 2.06 | 2.17 | 2.28 |
| 180 cm | 1.58 | 1.73 | 1.87 | 2 | 2.12 | 2.24 | 2.35 |
| 190 cm | 1.62 | 1.78 | 1.92 | 2.05 | 2.18 | 2.3 | 2.41 |
How the formulas compare
| Person | Mosteller | Du Bois & Du Bois | Haycock | Gehan & George | Boyd |
|---|---|---|---|---|---|
| Child, 110 cm, 18 kg | 0.74 | 0.74 | 0.74 | 0.76 | 0.76 |
| Adult, 160 cm, 55 kg | 1.56 | 1.56 | 1.57 | 1.58 | 1.58 |
| Adult, 175 cm, 72 kg | 1.87 | 1.87 | 1.87 | 1.88 | 1.88 |
| Adult, 185 cm, 110 kg | 2.38 | 2.33 | 2.41 | 2.39 | 2.4 |
The formulas agree closely for average adults and drift apart at the extremes. Haycock's paper found that Du Bois increasingly underestimated surface area below about 0.7 m², most in newborns, which is one reason Haycock or Mosteller is often preferred for children.
Where BSA is used
- Medicine dosing. Many chemotherapy drugs and some others are dosed in mg per m². The prescriber and pharmacist set and check every dose.
- Kidney function. eGFR is reported per 1.73 m², the surface area of an average adult; see the GFR calculator.
- Heart and lung tests. Cardiac index divides cardiac output by BSA so results can be compared between people of different sizes.
- Burns. Burn size is described as a percentage of total body surface area, which guides fluid treatment.
Related: the lean body mass calculator and the BMI calculator. This is not medical advice; talk to a doctor or registered dietitian.
Sources
- Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317(17):1098.
- 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.
- Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area. J Pediatr 1978;93(1):62–66.
- Gehan EA, George SL. Estimation of human body surface area from height and weight. Cancer Chemother Rep 1970;54(4):225–235.
- Boyd E. The Growth of the Surface Area of the Human Body. University of Minnesota Press, 1935.
Frequently asked questions
How do you calculate body surface area?
The simplest formula is Mosteller’s: multiply height in centimeters by weight in kilograms, divide by 3,600 and take the square root. Someone 180 cm tall weighing 80 kg has a BSA of √(180 × 80 ÷ 3600) = √4 = 2.00 m².
What is a normal body surface area?
For adults it is usually between about 1.6 and 2.2 m². A person 5 ft 9 in tall weighing 160 lb has a BSA of about 1.88 m² by the Mosteller formula. Many lab results are scaled to a standard 1.73 m² adult.
Which BSA formula is best?
For most adults the formulas agree within a few percent, so the choice rarely matters. Mosteller is the most widely used because it is easy to calculate, Du Bois is the oldest, and Haycock was validated from infants to adults. Hospitals usually set one formula for consistency.
Why is body surface area used in medicine?
BSA tracks metabolic size better than weight alone, so it is used to dose some chemotherapy and other medicines, to scale kidney function (eGFR is reported per 1.73 m²) and to index heart output. Doses are always set and checked by the care team.
Does body surface area work for children?
Yes. The Haycock formula was built from measurements of infants, children and adults. For a child 110 cm tall weighing 18 kg it gives about 0.74 m², very close to Mosteller and Du Bois at that size.