Body Surface Area Calculator
Calculate body surface area (BSA) in square meters from height and weight, using the Mosteller, Du Bois, Haycock and Gehan and George formulas.
Results
| Item | Value |
|---|
Quick Answer
The Mosteller formula is BSA (m²) = √(height in cm × weight in kg ÷ 3600). A person who is 5 ft 9 in and 170 lb has a BSA of about 1.94 m². The Du Bois formula gives 1.93 m² for the same person.
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Table of Contents
- Body Surface Area Calculator
- Quick Answer
- Related Calculators
- How This Body Surface Area Calculator Works
- How to Use the Body Surface Area Calculator
- Core Formulas
- Key Terms
- Worked Example
- Real-Life Examples
- BSA vs BMI
- BSA by Height and Weight (Mosteller)
- What BSA Is Used For
- Common Mistakes to Avoid
- Frequently Asked Questions
- References & Sources
How This Body Surface Area Calculator Works
Choose US or metric units and enter height and weight. The calculator converts them to centimeters and kilograms, then applies four published formulas. It shows each result in square meters, their average, and the Mosteller result in square feet.
Quick explanation: BSA estimates the total area of the skin, which relates to metabolism better than weight alone.
- Mosteller: simple and widely used.
- Du Bois: the most widely used historically, from 1916.
- Haycock and Gehan and George: often used for children and in research.
How to Use the Body Surface Area Calculator
- Choose US or metric units.
- Enter weight.
- Enter height in feet and inches, or centimeters.
- Press Calculate.
- Compare the four BSA results and their average.
Core Formulas
- Mosteller: √(H × W ÷ 3600)
- Du Bois: 0.007184 × W^0.425 × H^0.725
- Haycock: 0.024265 × W^0.5378 × H^0.3964
- Gehan and George: 0.0235 × W^0.51456 × H^0.42246
H is height in centimeters and W is weight in kilograms. Results are in square meters (m²).
Key Terms
- Body surface area (BSA): the estimated total surface area of the body, in square meters.
- m²: square meters. 1 m² is about 10.76 square feet.
- GFR: glomerular filtration rate, a measure of kidney function often given per 1.73 m².
- Cardiac index: cardiac output divided by BSA.
- Mosteller formula: a simple BSA formula: the square root of height times weight divided by 3600.
Worked Example
An adult is 175 cm tall and weighs 70 kg.
- Mosteller = √(175 × 70 ÷ 3600) = √3.403 = 1.84 m²
- Du Bois = 0.007184 × 70^0.425 × 175^0.725 = 1.85 m²
- The formulas agree within about 0.01 m²
Real-Life Examples
- A smaller adult: 5 ft 2 in and 120 lb gives a Mosteller BSA of 1.54 m².
- A larger adult: 6 ft 2 in and 230 lb gives 2.33 m².
- A child: 120 cm and 25 kg gives 0.91 m² with Mosteller and 0.91 m² with Haycock.
- Understanding a lab report: eGFR per 1.73 m² compares your kidney function to a standard body size.
BSA vs BMI
- BSA: an estimate of skin area in square meters. Used mainly for medicine doses and body-size adjustments.
- BMI: weight divided by height squared. Used to screen for underweight and overweight.
- Different jobs: a high BSA simply means a larger body, not an unhealthy one.
BSA by Height and Weight (Mosteller)
| Height | 120 lb | 150 lb | 180 lb | 210 lb |
|---|---|---|---|---|
| 5 ft 0 in | 1.52 | 1.70 | 1.86 | 2.01 |
| 5 ft 3 in | 1.56 | 1.74 | 1.91 | 2.06 |
| 5 ft 6 in | 1.59 | 1.78 | 1.95 | 2.11 |
| 5 ft 9 in | 1.63 | 1.82 | 1.99 | 2.15 |
| 6 ft 0 in | 1.66 | 1.86 | 2.04 | 2.20 |
| 6 ft 3 in | 1.70 | 1.90 | 2.08 | 2.25 |
What BSA Is Used For
- Medicine doses: some drugs, such as many chemotherapy drugs, are dosed per square meter.
- Kidney function: GFR is often reported per 1.73 m² of BSA.
- Heart output: the cardiac index is cardiac output divided by BSA.
- Burns and fluids: BSA helps estimate needs in some treatments.
Common Mistakes to Avoid
- Mixing units. The formulas need centimeters and kilograms. This tool converts for you.
- Dosing medicine yourself. Doses must come from a doctor or pharmacist.
- Expecting one exact answer. Each formula gives a slightly different estimate.
- Using old measurements. Weigh and measure for an accurate result.
- Confusing BSA with BMI. They measure different things.
Frequently Asked Questions
The Mosteller formula is the simplest: BSA = √(height in cm × weight in kg ÷ 3600).
No single formula is best for everyone. Du Bois and Mosteller are the most widely used, and they give similar results for most adults.
It depends on body size. Many adults fall between about 1.5 and 2.2 m².
BSA relates to metabolism and blood volume better than weight alone for some drugs.
It adjusts a result, such as kidney function, to a standard adult body size of 1.73 m².
No. BSA is an area in square meters. BMI is weight divided by height squared.
The formulas work for children too, and Haycock and Gehan and George were developed with children included, but doses must come from a doctor.
Multiply by 10.764. A BSA of 1.9 m² is about 20.5 sq ft.
Yes. Losing weight lowers BSA, though less than in proportion to the weight lost.
They were built from different groups of people and fitted with different math.
Pounds with feet and inches, or kilograms with centimeters.
No. It is for information only.
References & Sources
| Source | Used For | Link |
|---|---|---|
| Wikipedia, Body surface area | The formulas and uses of BSA. | https://en.wikipedia.org/wiki/Body_surface_area |
| Mosteller RD (1987), Simplified calculation of body-surface area, N Engl J Med | The original Mosteller formula. | https://pubmed.ncbi.nlm.nih.gov/3657876/ |