Body Surface Area CalculatorFree online fitness & health calculator — instant results, no sign-up
BSA using Mosteller and Du Bois formulas.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Body Surface Area Calculator
This calculator estimates total body surface area (BSA) in square meters using both the Mosteller and Du Bois formulas. Clinicians, researchers, and fitness professionals use BSA to calculate metabolic rates, normalize cardiac output, and determine accurate medication dosages.
- Height
- Total standing body height measured in centimeters (cm), typically between 50 and 250 cm.
- Weight
- Total body weight measured in kilograms (kg), typically between 2 and 300 kg.
Formula and method
Mosteller: BSA = sqrt((h × w) / 3600) Du Bois: BSA = 0.007184 × h^0.725 × w^0.425
- BSABody surface area in square meters (m²)
- hHeight in centimeters (cm)
- wWeight in kilograms (kg)
The calculator takes height in centimeters and weight in kilograms, computes the surface area using both the Mosteller equation and the classical Du Bois power equation, and rounds each output to 3 decimal places.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Height175 cm
- Weight75 kg
Results
- Mosteller1.909 m²
- Du Bois1.903 m²
How to use the Body Surface Area Calculator
- 1Multiply height (cm) by weight (kg), divide the product by 3600, and take the square root to calculate the Mosteller BSA.
- 2Raise height (cm) to the power of 0.725 and weight (kg) to the power of 0.425.
- 3Multiply those two exponential values by 0.007184 to find the Du Bois BSA.
- 4Round both resulting values to three decimal places and append the unit m².
Reading your result
Average adult BSA is approximately 1.7 m² to 1.9 m², though it varies with height and body frame. Both formulas produce very similar results, with the Mosteller formula generally matching the Du Bois estimate within a fraction of a percent.
Limitations
These formulas rely strictly on two-dimensional gross metrics (height and weight) and do not account for individual body composition, such as differences in body fat percentage, muscular build, limb proportions, or amputations.
Common questions
Why do the Mosteller and Du Bois formulas show slightly different results?+
Each formula was derived using different regression datasets and mathematical models. Du Bois relies on unequal power exponents, while Mosteller uses a simplified geometric mean approximation.
Which BSA formula is preferred in clinical practice?+
The Mosteller formula is widely adopted in modern clinical settings due to its mathematical simplicity and demonstrated accuracy comparable to the Du Bois equation.
What is considered a normal body surface area for an adult?+
A standard reference adult is often cited around 1.73 m², with typical adult values ranging between 1.6 m² and 2.0 m² depending on sex, height, and weight.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.