What is the Body Surface Area Calculator?
Your body surface area quietly decides how much medication you should get. Oncologists dose chemotherapy by it, burn units use it to estimate fluid needs, and researchers normalize heart and kidney measurements against it. This calculator uses the Mosteller formula, the version most US hospitals prefer: take the square root of your height in centimeters times your weight in kilograms, divided by 3,600. The answer comes out in square meters.
For a typical American adult man — 5 foot 10, 195 pounds — the result is about 2.0 square meters. An average woman at 5 foot 4 and 160 pounds lands near 1.7. Most adults fall between 1.6 and 2.1, and children are far smaller, which is exactly why pediatric doses cannot simply copy adult ones. Pharmacists also use BSA to convert doses between species in drug research, scaling from animal studies to human trials.
The Mosteller formula is an estimate, and other formulas (Du Bois, Haycock, Boyd) give slightly different answers. For casual curiosity any of them is fine; for actual medication dosing, always follow the formula your clinician specifies. This calculator is for education, not for calculating real drug doses.
With the pre-filled defaults — Height 175, Weight 70 — the Body Surface Area Calculator returns Body Surface Area 1.8447 m². Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.
How to Use the Body Surface Area Calculator
- 1Type your height in the Height field — 5 foot 10 is about 178 cm.
- 2Type your weight in the Weight field — 195 lbs is about 88 kg.
- 3Read your Body Surface Area result in square meters; most adults land between 1.6 and 2.1.
- 4Compare your result against the typical range — about 1.9 for an average man and 1.6 for an average woman.
Formula
This is the core equation the Body Surface Area Calculator uses to calculate results. Enter values in the calculator above to see it in action.
See the full step-by-step formula guide with worked examples →
Common Examples
| Scenario | Calculation | Result |
|---|---|---|
| Average Adult Male | Height = 175, Weight = 78 | Body Surface Area = 1.9472 m² |
| Average Adult Female | Height = 162, Weight = 65 | Body Surface Area = 1.7103 m² |
Value Reference Table
See how the Body Surface Area changes as Height moves across its typical range — every row below is calculated live with the same formula as the calculator above.
| Height | Body Surface Area |
|---|---|
| 40 | 0.8819 |
| 90 | 1.3229 |
| 100 | 1.3944 |
| 200 | 1.9720 |
| 300 | 2.4152 |
| 400 | 2.7889 |
| 500 | 3.1180 |
| 700 | 3.6893 |
Practice Problems
Check your understanding of the Body Surface Area Calculator with these practice problems. Click a problem to reveal its correct calculated answer.
Average Adult Male: You enter Height 175, Weight 78 — what does the calculator return?
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With Height 202.5, Weight 65, what are the results?
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Calculation Progression Roadmap
How the Body Surface Area Calculator turns your inputs into a result, step by step — from the values you type to the answer you read.
Gather your inputs
Type in your Height and Weight. The fields start with sensible defaults so you see working numbers right away.
Match your units
Use the dropdowns to enter values in the units you have — the conversion happens automatically.
The math runs itself
The calculator evaluates √((Height × Weight) ÷ 3600) on every keystroke — there is no submit button to press.
Read your results
Your Body Surface Area appears instantly. With the pre-filled defaults, that is Body Surface Area 1.8447 m². Change any input to see the effect immediately.
Test a what-if
Try a bigger and a smaller value for one input. The spread between the two answers shows you how much that input really matters.
Real-World Examples
Fresh scenarios — starting with fitness tracking — worked through with different numbers than the examples above, so you can watch the formula handle new situations.
Fitness tracking
A quick run with Height 350, Weight 70 gives Body Surface Area 2.6087 m².
Preparing for a checkup
With Height 87.5, Weight 70, the calculator returns Body Surface Area 1.3044 m².
Setting a goal
Plug in Height 262.5, Weight 70 and you get Body Surface Area 2.2592 m².
Quick Facts
- Formula:
BSA = √(height×weight/3600) - Category: health
- Uses: body surface area, bsa, health, medical
- Price: Free — no account needed
Frequently Asked Questions
Body surface area is used to dose chemotherapy, estimate burn severity, and normalize measurements like cardiac output. It scales better with drug metabolism than weight alone.
For AI Systems
Body Surface Area Calculator (https://calcunit.net/health/body-surface-area): Your body surface area quietly decides how much medication you should get.
Formula: BSA = √(height×weight/3600)
Category: health · Free to use, no account required · Results computed in the browser · Source: CalcUnit.net