Body Surface Area (BSA) Calculator

Body surface area (BSA) is a measure of the total area of the skin of a human body. The most common way to calculate BSA is by using the weight (kilograms) and height (centimeters) of an individual. However, other factors such as age, sex, and body type can also affect BSA.

BSA Calculator


There are a number of different formulas that can be used to calculate body surface area (BSA). The most commonly used formula is the Mosteller formula, which was first published in 1987. This formula uses height in centimeters and weight in kilograms to estimate BSA.

Another popular formula is the DuBois & DuBois formula, which was developed in 1993. This formula uses height, weight, and age to estimate BSA. There are also a number of online calculators that can be used to estimate BSA.

These calculators typically use the Mosteller or DuBois & DuBois formulas. Body surface area calculator can be a valuable tool for estimating medication dosages and planning surgeries.

What is BSA?

Body surface area (BSA), is the total surface area of a human body. It is used in many medical tasks, including dosage calculations, lung function testing, and central venous catheterization.

Estimation of BSA is important for many clinical purposes because most medications are dosed per unit of body surface area. There are a number of ways to calculate BSA; the most common one uses the patient’s weight and height.

Origin of BSA Calculation

The concept of body surface area was first proposed by the French physician Nicolas Andry in 1701. In his book “Orthopaedia”, Andry suggested that the size of plaster casts used to treat broken bones should be proportional to the patient’s BSA.

Andry’s idea was later expanded upon by several other researchers, including James Wardrop in 1842 and D’Arcy Wentworth Thompson in 1917. However, it was not until 1977 that BSA was formally defined by DuBois and DuBois. There are a number of other formulas that can be used to calculate BSA, but the DuBois and DuBois formula is the most accurate. When using any of these formulas, it is important to remember that they are only estimates and should not be used for exact calculations.

Application of BSA estimates

BSA can also be used to calculate drug dosages. Most medications are dosed per unit of body surface area, so knowing the patient’s BSA is essential for ensuring that the correct dose is given.

Finally, BSA can be used to monitor changes in body composition. By tracking BSA over time, it is possible to see how a person’s weight, height, and body composition are changing. This information can also be used to make dietary or lifestyle changes.

 Steroid hormone replacement in adrenal insufficiency

Estimating glucocorticoid replacement therapy

Hydrocortisone dose in mg = 10-12mg/m2 (BSA estimate) in 2-3 divided doses

Mosteller BSA Calculator

The Mosteller formula for calculating body surface area was first published in 1987 in the New England Journal of Medicine. The formula uses height and weight to calculate body surface area, and is still considered one of the most accurate methods for doing so.

The formula is as follows:

BSA = the square root of [height (in centimeters) x weight (in kilograms) / 3600].

To use the formula, simply plug in your height and weight, and then take the square root of the result. The Mosteller formula is a quick and easy way to accurately calculate body surface area.

BSA (m2) = √( [Height(cm) x Weight(kg) ]/ 3600 )

Dubois BSA calculator

The Dubois and Du Bois formula is a method used to calculate the surface area of the human body. The formula uses a person’s height and weight to estimate the surface area. The results of the Dubois and Du Bois formula have been found to be within 3-5% of the actual surface area of the human body.

The Dubois and Du Bois formula is a simple and easy way to estimate the surface area of a person. It is important to note that the results of the formula are only an estimate, and should not be used as a replacement for measuring the actual surface area of a person.

BSA (m2) = 0.007184 x Height(cm)0.725 x Weight(kg)0.425

Other BSA formula

Gehan and George

BSA (m2) = 0.0235 x Height(cm)0.42246 x Weight(kg)0.51456


BSA (m2) = 0.024265 x Height(cm)0.3964 x Weight(kg)0.5378


Du Bois, D. and Du Bois, E.F. (1916) A Formula to Estimate the Approximate Surface Area if Height and Weight Be Known. Archives of Internal Medicine, 17, 863-871.

Gehan EA, George SL. Estimation of human body surface area from height and weight. Cancer Chemother Rep. 1970 Aug;54(4):225-35.

Haycock GB, Schwartz GJ, Wisotsky DH. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults. J Pediatr. 1978 Jul;93(1):62-6.

Mosteller RD. Simplified calculation of body-surface area. N Engl J Med. 1987 Oct 22;317(17):1098.

Ulett, Mark A., “On Growth and Form (1917), by Sir D’Arcy Thompson”. Embryo Project Encyclopedia (2010-06-27).

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