Body Surface Area Calculator
Use this BSA calculator to estimate your body surface area (BSA) in square feet and square meters. Useful for a number of health/fitness calculations.
What is BSA?
Body Surface Area (BSA) is simply a measurement of the surface area of your body. Since the body is a complex figure, making an accurate measurement of its surface is a considerable challenge. To address it, scientists in the early 1900s took measurements via melted paraffin and paper strips applied to their body. After removing the pieces, they were cut into regular shapes allowing accurate BSA calculation.
From these studies we have understanding of the relationship between height (stature) and body weight (mass) and a formula through which we can calculate a persons body surface area based in their weight and height. BSA calculations are useful when determining different body characteristics, for example energy expenditure in the form of BMR, RMR (REE), RDEE, TDEE, which are in turn used when determining dietary and nutritional needs.
Estimating Body Surface Area (BSA)
To estimate your body surface area our BSA calculator uses the following formula:
0.20247 x height (m)0.725 x mass (kg)0.425
where height is in meters and mass is in kg. The result is in squared meters, which easily be converted to square feet, inches or yards as needed. Below are some average values for different age groups in graph and table form.
This is a slight variation of the DuBois & DuBois body surface area formula, derived in 1916 , modified for easier calculation with height expressed in meters instead of centimeters and the results are practically identical. The DuBois & DuBois original formula is:
0.007184 x height (cm)0.725 x mass (kg)0.425
There are other competing formulae derived over the years (e.g. Breitmann in 1932, Stevenson in 1937, Haycock in 1978, Schlich in 2010) and a discussion about their accuracy is ongoing in the medical community, but the formula used in our BSA calculator is one of the most-commonly used by medical practitioners .
Both the chart and the tables with average body surface area estimates are based on weight and height data from the U.S. NCHS National Health and Nutrition Examination Survey (2011-2014) .
The graph clearly shows that values for boys and girls are almost identical up to 14 years of age, when they significantly departure with males having a mean BSA 10-15% higher than females due to differences in stature and weight (there is no gender component in the formula).
Mean male BSA by age table:
|Age or age group||BSA (m2)||BSA (ft2)|
|Neonate (newborn)||0.243 m2||2.612 ft2|
|1 years||0.467 m2||5.027 ft2|
|2 years||0.563 m2||6.060 ft2|
|3 years||0.634 m2||6.824 ft2|
|4 years||0.712 m2||7.664 ft2|
|5 years||0.787 m2||8.471 ft2|
|6 years||0.867 m2||0.332 ft2|
|7 years||0.965 m2||10.387 ft2|
|8 years||1.050 m2||11.302 ft2|
|9 years||1.116 m2||12.013 ft2|
|10 years||1.236 m2||13.304 ft2|
|11 years||1.371 m2||14.757 ft2|
|12 years||1.435 m2||15.446 ft2|
|13 years||1.603 m2||17.255 ft2|
|14 years||1.720 m2||18.514 ft2|
|15 years||1.825 m2||19.644 ft2|
|16 years||1.886 m2||20.301 ft2|
|17 years||1.907 m2||20.527 ft2|
|18 years||1.980 m2||21.313 ft2|
|19 years||1.958 m2||21.076 ft2|
|20-29 years||2.016 m2||21.700 ft2|
|30-39 years||2.072 m2||22.303 ft2|
|40-49 years||2.081 m2||22.340 ft2|
|50-59 years||2.070 m2||22.281 ft2|
|60-69 years||2.065 m2||22.227 ft2|
|70-79 years||1.998 m2||21.506 ft2|
|80+ years||1.920 m2||20.667 ft2|
Mean female BSA by age table:
|Age or age group||BSA m2||BSA ft2|
|Neonate (newborn)||0.234 m2||2.519 ft2|
|1 years||0.456 m2||4.908 ft2|
|2 years||0.540 m2||5.813 ft2|
|3 years||0.625 m2||6.727 ft2|
|4 years||0.702 m2||7.556 ft2|
|5 years||0.771 m2||8.299 ft2|
|6 years||0.862 m2||9.278 ft2|
|7 years||0.942 m2||10.140 ft2|
|8 years||1.051 m2||11.313 ft2|
|9 years||1.163 m2||12.518 ft2|
|10 years||1.245 m2||13.401 ft2|
|11 years||1.361 m2||14.650 ft2|
|12 years||1.512 m2||16.275 ft2|
|13 years||1.550 m2||16.684 ft2|
|14 years||1.621 m2||17.448 ft2|
|15 years||1.685 m2||18.137 ft2|
|16 years||1.698 m2||18.277 ft2|
|17 years||1.727 m2||18.589 ft2|
|18 years||1.726 m2||18.579 ft2|
|19 years||1.741 m2||18.740 ft2|
|20-29 years||1.790 m2||19.267 ft2|
|30-39 years||1.845 m2||19.859 ft2|
|40-49 years||1.842 m2||19.827 ft2|
|50-59 years||1.840 m2||19.806 ft2|
|60-69 years||1.804 m2||19.418 ft2|
|70-79 years||1.780 m2||19.160 ft2|
|80+ years||1.638 m2||17.631 ft2|
Body surface area in squared meters and squared feet in the graph and tables is calculated using our body surface area calculator. It should be noted that the mean and the median values, at least for children and adolescents of age 0-20 differ significantly, with the median being significantly lower than the mean, suggesting that the distribution is affect by a relatively small number of overweight and obese individuals. Take this into account when interpreting the data.
Applications for BSA
Body surface area is used to calculate the resting energy expenditure, also known as resting metabolic rate when the rate required is per square meter per hour, and not the daily rate. The same applies for total daily energy expenditure calculations.
BSA is also used to determine the dosage of medications, to estimate renal clearance, in chemotherapy dosage, glucocorticoid dosage and in the composition of the cardiac index. Several antivirals, antimicrobials, and antifungals require a dosing regimen based on the BSA . Estimations related to organ transplantation often use the body surface area as an important metric.
 Katch V.L., McArdle W.D., Katch F.I (2011) "Essentials of Exercise Physiology", fourth edition
 US NCHS (2016) "National Health and Nutrition Examination Survey (2011-2014)" DHHS Publication No. 1604, s.3, N 39
 Redlarski G., Palkowski A., Krawczuk M. (2016) "Body surface area formulae: an alarming ambiguity" Scientific Reports 6, article 27966
 Du Bois D. & 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
Cite this calculator & page
If you'd like to cite this online calculator resource and information as provided on the page, you can use the following citation:
Georgiev G.Z., "Body Surface Area Calculator", [online] Available at: https://www.gigacalculator.com/calculators/bsa-calculator.php URL [Accessed Date: 17 Apr, 2021].