Body Surface Area Calculator – Calculate Your BSA (2024)

Calculate your body surface area given your height and weight.

What is Body Surface Area?

Body surface area (BSA) is a clinical measurement used most often in the medical field to dose medications.^[1] It is also used in cardiology to estimate effective cardiac output based on a person’s size.^[2]

This is known as the cardiac index. In nephrology, body surface area is also used to determine the true glomerular filtration rate on an individual basis by dividing a patient’s calculated GFR by their BSA.^[2]

If you’re trying to calculate body shape, then you might consider using our body shape calculator instead.

How to Calculate BSA

There are several different formulas used to calculate BSA using an individual’s height and weight. Body surface area is measured in meters squared (m²).

BSA Formulas

Similar to body mass index calculations, these formulas use your height in centimeters and weight in kilograms to calculate the final BSA. Since the calculations themselves require complicated mathematics, having a body surface area calculator comes in handy if you need to determine BSA quickly.

The formulas below all use the weight in kilograms and height in centimeters. You can use our pounds to kilograms or inches to centimeters conversion calculators if needed.

DuBois Formula:

The DuBois formula is the most widely used calculation in medicine, despite the fact that it was derived from a study using only nine individuals. However, more recent studies have validated its use as well.^[3]

BSA = 0.007184 × weight^0.425 × height^0.725

Mosteller Formula:

The Mosteller formula is often recommended to compute BSA since it is much simpler than other body surface area formulas.^[4]

BSA = 0.016667 × weight^0.5 × height^0.5

Hayco*ck Formula:

After finding that the DuBois formula underestimated BSA for values below 0.7 m2, a study using calculations and nomograms helped develop the Hayco*ck formula to compute BSA.^[5]

BSA = 0.024265 × weight^0.5378 × height^0.3964

Gehan and George Formula:

The Gehan and George formula was derived using similar models as the DuBois formula. However, this was based on data from 401 direct measurements of BSA, as compared to only nine measurements used to develop the DuBois formula.^[6]

BSA = 0.0235 × weight^0.51456 × height^0.42246

Boyd Formula:

The Boyd formula can also be used to estimate body surface area. This was based on a comprehensive comparison of various methods used to calculate BSA.^[7]

BSA = 0.0333 × weight^{(0.6157 – 0.0188 × log10(weight))} × height^0.3

Fujimoto Formula:

The Fujimoto formula took body surface areas from actual measurements of body weight, height, and surface area on 201 Japanese from neonatal to old age, and then compared and examined this data. From this, the following formula was determined to be the most representative for Japanese over six years of age.^[8]

BSA = 0.008883 × weight^0.444 × height^0.663

Takahira Formula:

Takahira and colleagues developed a body surface area formula based on the regional rates in Japan by race, sex, and age.^[9] The Fujimoto formula was later developed as it was thought there was a higher error rate in the Takahira formula.

BSA = 0.007241 × weight^0.425 × height^0.725

Shuter & Aslani Formula:

Shuter and Aslani derived a formula by revisiting the data from the original DuBois equation and expanding the number of patients studied from 9 to 42 to derive a formula based on a more adequate sample size.^[10]

BSA = 0.00949 × weight^0.441 × height^0.655

Lipscombe Formula:

Lipscombe developed a formula based on geometric measurements to estimate body surface area.^[11]

BSA = 0.00878108 × weight^0.434972 × height^0.67844

Schlich Formula:

The Schlich formula was derived from Laser-supported body scanning to measure active heat exchange over the body surface in 188 individuals. This sophisticated method came up with the following equation, which differs between men and women.^[12][13]

Women:
BSA = 0.000975482 × weight^0.46 × height^1.08

Men:
BSA = 0.000579479 × weight^0.38 × height^1.24

Calculating Body Surface Area

As you can see, there are numerous equations that have been developed over the years to try to estimate body surface area. However, the development of three-dimensional laser scanning and graphics editing software may provide a more accurate determination of body surface area.

In one study, different BSA prediction formulas were tested and compared against this three-dimensional scanning. These formulas included DuBois, Boyd, Gehan and George, Hayco*ck, Mosteller, and the Shuter & Aslani formulas.

Although most predict the measured BSA closely, there can be an overprediction with increasing body size.^[14] In general, however, any of these equations can give a good estimate of body surface area.