Body Surface Area Calculator
Body surface area (BSA) is the total surface area of the human body in square metres, and it is often used to dose medication more accurately than body weight alone. This calculator computes your BSA with the four most trusted formulas — Du Bois, Mosteller, Haycock and Gehan-George — so you can compare the results.
How to calculate Body Surface Area?
The BSA Calculator uses four different methods to calculate the body surface area:
- DuBois D, DuBois DF. A formula to estimate the approximate surface area if height and weight be known. Arch Int Med 1916;17:863-71. BSA calculator formula for this method: BSA(m2) = 0.007184 * Height(cm)0.725 * Weight(kg)0.425
- 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;93:62-6. BSA calculator formula for this method: BSA (m2) = 0.024265 * Height(cm)0.3964 * Weight(kg)0.5378
- Gehan EA, George SL. Estimation of human body surface area from height and weight. Cancer Chemother Rep 1970;54:225-35. BSA calculator formula for this method: BSA (m2) = 0.0235 * Height(cm)0.42246 * Weight(kg)0.51456
- Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317:1098. BSA calculator formula for this method: BSA (m2) = [(Height(cm) * Weight(kg))/3600]0.5
The most widely used formula for calculating Body Surface Area is the Du Bois formula, which has been shown to be equally as effective in estimating body fat in obese and non-obese patients, something the Body mass index fails to do.
How to use the Body Surface Area Calculator?
Select the unit first (imperial or metric) for BSA Calculation. Enter your height and weight and then click on the Calculate button of the BSA Calculator. The BSA Calculation results are shown immediately.
What is Body Surface Area Calculation used for?
Body Surface Area Calculation is used for clinical purposes, for example, to calculate drug dosages and medical indicators or assessments. BSA seems to be a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass.
Average values for Body Surface Area by age and gender
BSA Calculator: Average Male BSA Values
| AGE | IMPERIAL | METRIC | ||
| Neonate (newborn) | 2.612 | ft2 | 0.243 | m2 |
| 2 years | 6.060 | ft2 | 0.563 | m2 |
| 5 years | 8.471 | ft2 | 0.787 | m2 |
| 10 years | 13.304 | ft2 | 1.236 | m2 |
| 13 years | 17.255 | ft2 | 1.603 | m2 |
| 18 years | 21.313 | ft2 | 1.980 | m2 |
| 20-79 years | 22.173 | ft2 | 2.060 | m2 |
| 80+ years | 20.667 | ft2 | 1.920 | m2 |
BSA Calculator: Average Female BSA Values
| AGE | IMPERIAL | METRIC | ||
| Neonate (newborn) | 2.519 | ft2 | 0.234 | m2 |
| 2 years | 5.813 | ft2 | 0.540 | m2 |
| 5 years | 8.299 | ft2 | 0.771 | m2 |
| 10 years | 13.401 | ft2 | 1.245 | m2 |
| 13 years | 16.684 | ft2 | 1.550 | m2 |
| 18 years | 18.579 | ft2 | 1.726 | m2 |
| 20-79 years | 19.697 | ft2 | 1.830 | m2 |
| 80+ years | 17.631 | ft2 | 1.638 | m2 |
Body Surface Area averages in the tables above are based weight and height data from the U.S. NCHS National Health and Nutrition Examination Survey (2011-2014)
Frequently asked questions
How is body surface area calculated?
BSA is estimated from your height and weight using a formula such as Mosteller, where BSA in m² equals the square root of height in cm times weight in kg divided by 3600.
What is the average body surface area?
The average adult BSA is about 1.7 m². It is roughly 1.9 m² for men and 1.6 m² for women, though it varies with height and weight.
Why is BSA used for medication dosing?
BSA correlates better with metabolic rate and organ size than weight alone, so it is widely used to calculate doses of chemotherapy and other drugs.
Which BSA formula is most accurate?
The Du Bois and Mosteller formulas are the most commonly used. Mosteller is popular because it is simple, while Du Bois has a long clinical track record.
What units is body surface area measured in?
BSA is measured in square metres (m²). Most clinical formulas take height in centimetres and weight in kilograms.