Body Surface Area Calculator
Estimate body surface area from height and weight for medical dosing.
This bsa calculator estimates Body Surface Area - the total external surface area of the human body - from height and weight, using standard medical formulas like Mosteller or DuBois. BSA is commonly used in medical settings for medication dosing and certain diagnostic calculations.
Enter height and weight, and the calculator returns your estimated body surface area in square meters.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| Height 170 cm, weight 70 kg | BSA ≈ 1.82 m² | BSA = √[(170 × 70) ÷ 3600] = √(11,900 ÷ 3600) = √3.306 ≈ 1.82 m². |
| Height 155 cm, weight 50 kg | BSA ≈ 1.47 m² | BSA = √[(155 × 50) ÷ 3600] = √(7,750 ÷ 3600) = √2.153 ≈ 1.47 m². |
The Body Surface Area Formula
The widely used Mosteller formula is: BSA = sqrt((height in cm x weight in kg) / 3600). It's valued for being simple to calculate while remaining reasonably accurate compared to more complex historical formulas like DuBois.
Why BSA Matters More Than Weight Alone for Dosing
Some medications, particularly chemotherapy drugs, are dosed based on BSA rather than weight alone, since BSA correlates more closely with metabolic processes and organ function across different body sizes than weight does by itself.
How to Use the Body Surface Area Calculator
- Open the Body Surface Area Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the body surface area calculator works.
Frequently Asked Questions
What is the body surface area formula?
The Mosteller formula is BSA = sqrt((height in cm x weight in kg) / 3600), returning body surface area in square meters.
Why is BSA used for medication dosing?
BSA correlates well with metabolic rate and organ function across different body sizes, making it a more precise dosing reference than weight alone for certain drugs, especially chemotherapy.
Is this bsa calculator a substitute for medical advice?
No, this is a general reference estimate only. Actual medical dosing decisions should always be made by a qualified healthcare provider using validated clinical formulas.
How do I use this body surface area calculator?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Body Surface Area Calculator calculate?
Estimate body surface area from height and weight for medical dosing. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this body surface area use?
The formula is: Mosteller: BSA = √[(height(cm) × weight(kg)) ÷ 3600]. The DuBois formula, published by father-son researchers Delafield and Eugene DuBois in 1916, was based on surface measurements taken from just nine actual patients - a remarkably small sample by modern standards that nonetheless remained the medical standard for decades. The simpler Mosteller formula, published in 1987, was designed to be easier to calculate by hand while still closely matching DuBois's results, and both remain in clinical use for medication dosing calculations that scale better with body surface area than with weight alone.
Related Calculators
Blood Pressure Category Calculator
Estimate Blood Pressure Category values for health, wellness, and lifestyle planning.
A1C to Average Glucose Calculator
Estimate A1C to average glucose values for health, wellness, and lifestyle planning.
Insulin Dose Calculator
Estimate Insulin Dose values for health, wellness, and lifestyle planning.
BMI Calculator
Compute your Body Mass Index (BMI) and health category based on height and weight.
Calories Calculator
Estimate daily calorie intake (TDEE & BMR) for weight loss or muscle gain.
Ideal Weight Calculator
Calculate ideal body weight target based on height, gender, and frame size.
Last updated: September 27, 2026.