Body Surface Area Calculator
The calculator below computes the total surface area of a human body, referred to as body surface area (BSA). Direct measurement of BSA is difficult, and as such many formulas have been published that estimate BSA. The calculator below provides results for some of the most popular formulas.
Result
The following are the body surface area results based on popular formulas:
Formula  Results in different units  
Du Bois  1.85 m^{2}  19.95 ft^{2}  2,873 in^{2} 
Mosteller  1.85 m^{2}  19.91 ft^{2}  2,868 in^{2} 
Haycock  1.85 m^{2}  19.94 ft^{2}  2,871 in^{2} 
Gehan & George  1.86 m^{2}  20.01 ft^{2}  2,882 in^{2} 
Boyd  1.86 m^{2}  19.98 ft^{2}  2,877 in^{2} 
Fujimoto  1.79 m^{2}  19.30 ft^{2}  2,779 in^{2} 
Takahira  1.87 m^{2}  20.11 ft^{2}  2,896 in^{2} 
Schlich  1.77 m^{2}  19.01 ft^{2}  2,738 in^{2} 
The Body Mass Index (BMI) of the given weight and height is 22.9 kg/m^{2}.

Table of average BSAs
ft^{2}  m^{2}  
Newborn child  2.69  0.25 
Twoyearold child  5.38  0.5 
Tenyearold child  12.27  1.14 
Adult female  17.22  1.6 
Adult male  20.45  1.9 
BSA is often used in clinical purposes over body weight because it is a more accurate indicator of metabolic mass (the body's need for energy). Metabolic mass can be estimated using fatfree mass, where fatfree mass is all of a person's body mass that does not include fat. This includes bones, tendons, inner organs, muscles, blood, nerves, and more. Since body fat is not metabolically active and fatfree mass excludes body fat, fatfree mass is a reasonable estimate of metabolic mass.
BSA is also used in various other clinical settings, such as determining cardiac index (to relate a person's heart performance to their body size) or most commonly, dosages for chemotherapy (a category of cancer treatment). While dosing for chemotherapy is often determined using a patient's BSA, there exist arguments against the use of BSA to determine medication dosages that have a narrow therapeutic index – the comparison of the amount of a substance necessary to produce a therapeutic effect, to the amount that causes toxicity. If the therapeutic index is too narrow, BSA may not be an accurate enough measure, and there is a risk of causing a toxic rather than therapeutic effect. There is also evidence that BSA becomes less accurate at the extremes of height and weight, and BMI may be a better estimate in such cases. Despite these limitations, the effects of chemotherapy dosages as determined by BSA measurements still remain more consistent than those determined by body weight alone.
Below are some of the most popular formulas for estimating BSA, and links to references for each for further detail on their derivations. The most widely used of these is the Du Bois formula, which has been shown to be effective for estimating body fat in both obese and nonobese patients, unlike body mass index. Where BSA is represented in m^{2}, W is weight in kg, and H is height in cm, the formulas are as follows: