BSA Calculator - Body Surface Area

Created by James Mathison, Mateusz Mucha and Dominika Śmiałek, MD, PhD candidate
Reviewed by Jack Bowater
Based on research by
Burton, R. Estimating body surface area from mass and height: theory and the formula of Du Bois and Du Bois Annals of Human Biology (July 2009)See 4 more sources
Mosteller, R. Simplified calculation of body-surface area The New England Journal of Medicine (October 1987)Haycock, G.; Schwartz, G.; Wisotsky, D. Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults The Journal of Pediatrics (July 1987)Gehan, E.; George, S. Estimation of human body surface area from height and weight Cancer Chemother Rep (August 1970)Fujimoto, S.; et al. Studies on the Physical Surface Area of Japanese Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) (1968)
Last updated: Jan 04, 2023

The BSA calculator allows you to easily find your body surface area (BSA), which is the external surface area of the human body given in square meters. If you know how to calculate BSA, you will find it very useful in medicine and physiology, as it is a more accurate indicator of metabolism than body weight. This is why many doctors base their prescriptions on the BSA formula.

However, you may simply find it interesting to calculate your body surface area. Scientists have established that the whole human circulatory system is over twice as long as the circumference of the Earth if you were to stretch it out. If you know how to calculate BSA, you can find out how many square meters the surface of your body would cover if it could be unraveled and laid out. We hope you find this more interesting than morbid.

Keep reading if you would like to find out:

  • What the BSA formula is, and how it can be used to calculate body area;
  • What body surface area calculator is;
  • How to calculate BSA;
  • What other calculators you should check out if you are interested in this topic.

Disclaimer: We try our best to make our Omni Calculators as precise and reliable as possible. However, this tool can never replace professional medical advice.

The BSA formula

Many different formulas can be used to calculate body surface area. Our BSA calculator uses the most common form, the Du Bois formula, by default. There are, however, many different BSA formulas in the advanced mode (Mosteller, Haycock, Gehan and George, Boyd, Fujimoto, Takahira, Shuter, and Aslani and Schlich separately for men and women). All you need to use any of these formulas is your weight and height. Let's take a look at a few of them.

Here are the formulas:

  • Du Bois:
BSA=0.007184weight0.425height0.725\footnotesize \text{BSA} \!\!= \!\!0.007184 \!\cdot \!\text{weight}^{0.425} \!\!\cdot\! \text{height}^{0.725}
  • Mosteller:
BSA [m2]=height [cm]weight [kg]3600\footnotesize \text{BSA [m}^2] \!\!= \!\!\sqrt{\frac{\text{height [cm]} \cdot \text{weight [kg]}}{3600}}
  • Haycock:
BSA=0.024265weight0.5378height0.3964\footnotesize \text{BSA} \!\!= \!\!0.024265 \!\cdot \!\text{weight}^{0.5378} \!\!\cdot\! \text{height}^{0.3964}
  • Gehan and George:
BSA=0.0235weight0.51456height0.42246\footnotesize \text{BSA} \!\!= \!\!0.0235 \!\cdot \!\text{weight}^{0.51456} \!\!\cdot\! \text{height}^{0.42246}
  • Fujimoto:
BSA=0.008883weight0.444height0.663\footnotesize \text{BSA} \!\!= \!\!0.008883 \!\cdot \!\text{weight}^{0.444} \!\!\cdot\! \text{height}^{0.663}

where BSA is measured in square meters, weight in kilograms, and height in centimeters. Our tool lets you easily use other units, so don't worry.

Let's try one calculation using the Mosteller formula:

  1. Take your height in centimeters, e.g. 170;
  2. Take your weight in kilograms, e.g.60;
  3. Multiply your height by your weight, 170x60 = 10200;
  4. Divide the result by 3600, 10200/ 3600 = 2.8;
  5. Find the square root of the result, SQRT 2.8 = 1.67.

If you are 170 cm tall and weigh 60 kg, the approximate calculation of your body surface area is 1.67 meters squared.

Some medical practitioners prefer other BSA formulas, such as Haycock, or Gehan & George.

Why use this body surface area calculator?

Luckily for you, there's no need to calculate your BSA on your own. You can avoid any tedious calculations by using the body surface area calculator. Thanks to this tool, you can find the size of your body if it was a flat area. Although the calculator is based on some complicated equations, it is simple to use and only takes a few seconds if you already know your height and weight.

It turns out that knowing how to calculate your BSA can give you insight into your level of health that other metrics can't. For example, your body surface area is a predictor of coronary artery calcium, a serious medical concern. This makes BSA better than body mass index, as, while good for analyzing your general health status based on weight, BMI cannot predict this condition.

How to calculate BSA

The easiest way to calculate your body surface area is to use our BSA calculator. This tool needs only your weight and height to solve the equation. After plugging in these two values, you automatically get a result.

Let's check our previous example:

  1. Weight (kg): 60
  2. Height (cm): 170

With these measurements, your body surface area equals about 1.69 square meters.

If you are going to calculate your BSA, it's good to know the average BSA values. They are divided into categories of age and gender.

The average body surface area for:

  • Infants: 0.25 m²
  • Children of 2 years: 0.5m²
  • Children of 10 years: 1.14m²
  • Women: 1.6m²
  • Men: 1.9m²

Other considerations

If you are interested in different measurements related to your body, you should also check our BMI calculator. This is a tool that you can use to discover if your weight is in a healthy range or not. Another calculator you might find useful is our water intake calculator.

It is worth noting that, although BSA is a good indicator of metabolic rate, it has received some critique. The most important of which is to use it to determine the dosage of medications that don't have much margin for error, such as chemotherapy.

James Mathison, Mateusz Mucha and Dominika Śmiałek, MD, PhD candidate
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