Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate body surface area (BSA) using the Mosteller formula.
1.84 m²
Body Surface Area (BSA) is an estimate of the total surface area of the human body, commonly used in some clinical contexts (like medication dosing calculations). This tool uses the Mosteller formula (1987) -- the simplest and most widely used of the several published BSA formulas.
Enter your height in centimeters and weight in kilograms. Estimated BSA in square meters appears instantly.
BSA (m²) = √((Height(cm) × Weight(kg)) / 3600)
This tool is for general informational purposes only and is not a substitute for clinical medication dosing calculations, which must be performed by a qualified healthcare provider using validated clinical protocols. Never use this tool's output to determine medication dosages.
Take a hypothetical adult who is 175 cm tall and weighs 70 kg. Multiplying gives 12,250, dividing by 3,600 gives 3.4028, and the square root is about 1.84 square meters. A smaller person at 160 cm and 55 kg gives 8,800 / 3,600 = 2.444, whose square root is about 1.56 m². A larger person at 190 cm and 100 kg gives 19,000 / 3,600 = 5.278, and the root is about 2.30 m². The result is shown to two decimals.
BSA = square root of (Height in cm x Weight in kg / 3600)
Because the formula uses a square root of a product, BSA grows more slowly than either height or weight alone. Doubling your weight while staying the same height raises BSA by only about 41 percent, not 100 percent. That is one reason BSA is used as a scaling measure: it changes gently as body size changes.
BSA is a size-scaling value rather than a health score. A higher figure is not good or bad by itself; it simply reflects a larger body surface. In clinical practice it sometimes appears in calculations for certain treatments, physiological measurements that are normalized to body size, and some burn assessments. The Mosteller formula is one of several published methods, and others such as DuBois can give slightly different values for the same person, with the differences tending to be small for typical adult sizes.
The formula is an approximation derived from population data, and it does not account for body composition. Two people with the same height and weight get the same BSA even if one carries much more muscle or fat. It may be less reliable for infants, children, very small or very large bodies, and people with unusual proportions, for whom clinicians may use different methods.
Most importantly, this is not a dosing tool. Where medication doses are based on body surface area, the calculation is done by trained clinicians using protocols that specify the formula, rounding rules, and dose caps. Do not use a figure from this page to adjust or decide any medication dose. If you are curious about a BSA value in your own medical paperwork, ask your care team to explain it.
The tool is best used for learning how BSA relates to height and weight or for cross-checking a value you have seen in a textbook or article. This page is educational and not medical advice.
In clinical settings, it's sometimes used as a basis for medication dosing (particularly in oncology) since some drugs are dosed relative to body surface area rather than weight alone -- this is a specialized medical calculation, not something to self-apply.
It's valued for its simplicity (a single square-root formula) while still correlating well with more complex BSA formulas across most body types.
No -- medication dosing must be determined by a qualified healthcare provider using validated clinical protocols, not a general calculator.
Yes, but modestly, since the formula uses a square root. For a person of fixed height, a 10 percent weight change alters BSA by about 5 percent.
Several BSA formulas exist, such as Mosteller and DuBois, and they use different mathematical forms. This tool uses Mosteller only, so small differences from other sites are expected.
It falls in a range typical for many adults, though average values differ by population. It is a size measure, not a judgment of health.
No, the field is in centimeters. Multiply inches by 2.54 first.
Reference: Centers for Disease Control and Prevention