Calculator inputs
The page stays single column, while the input area shifts to three, two, or one columns by screen width.
Example data table
| Profile | Sex | Height (cm) | Weight (kg) | Mosteller (m²) | Du Bois (m²) | Haycock (m²) |
|---|---|---|---|---|---|---|
| Adult A | Male | 170 | 70 | 1.818 | 1.81 | 1.826 |
| Adult B | Female | 160 | 55 | 1.563 | 1.563 | 1.566 |
| Adult C | Male | 182 | 92 | 2.157 | 2.136 | 2.173 |
| Teen D | Female | 148 | 42 | 1.314 | 1.317 | 1.313 |
Formula used
Body surface area estimates body size in square meters. This calculator supports several common equations so you can compare outputs instead of relying on one method only.
| Formula | Expression | Notes |
|---|---|---|
| Mosteller | BSA = √((height cm × weight kg) / 3600) | Common quick method for everyday calculation. |
| Du Bois | BSA = 0.007184 × weight^0.425 × height^0.725 | Classic height and weight equation. |
| Haycock | BSA = 0.024265 × weight^0.5378 × height^0.3964 | Often used when comparing pediatric and adult sizes. |
| Gehan-George | BSA = 0.0235 × weight^0.51456 × height^0.42246 | Alternative nonlinear estimate using both measures. |
| Boyd | BSA = 0.0003207 × (weight g)^(0.7285 − 0.0188×log10(weight g)) × height^0.3 | Adjusts the weight exponent using body mass size. |
| Fujimoto | BSA = 0.008883 × weight^0.444 × height^0.663 | Another height and weight estimate for comparison. |
| Schlich | Male and female equations use different constants and exponents. | Sex selection is required before this result appears. |
Metric values are used internally. Imperial entries are converted to centimeters and kilograms before calculation.
How to use this calculator
- Choose metric or imperial units.
- Enter height and weight carefully.
- Select sex if you want the Schlich estimate.
- Pick the formulas you want to compare.
- Choose the formula that should appear as the primary result.
- Set decimal precision, then press Calculate BSA.
- Review the result card, comparison table, and graph.
- Use the CSV or PDF buttons to save your report.
Frequently asked questions
1. What is body surface area?
Body surface area is an estimate of total external body size, usually expressed in square meters. It is often used when comparing physiologic size or reviewing medicine and treatment calculations.
2. Why do different formulas give different answers?
Each equation was derived from different populations and fitting methods. Small differences are expected, so comparing several formulas can show how much your estimate varies.
3. Which formula should I treat as primary?
Use the formula your clinic, study, or protocol specifies. When no rule is provided, Mosteller is often chosen for simplicity, but local practice should guide final use.
4. Can I use imperial units?
Yes. The calculator accepts feet, inches, and pounds. It converts them to metric values behind the scenes before applying the selected equations.
5. Does this replace clinical judgment?
No. This tool is for estimation and review. Drug dosing, burn care, transplant sizing, and other treatment decisions should follow professional guidance and verified protocols.
6. Why is sex requested?
The Schlich equation uses different coefficients for male and female inputs. If sex is left unspecified, the calculator simply skips that formula and reports the others.
7. What does formula spread mean?
Spread is the difference between the highest and lowest BSA value from your selected formulas. A larger spread means the formulas disagree more for those inputs.
8. What do the export buttons save?
The CSV file saves the formula table for spreadsheet use. The PDF button saves the visible result report so you can print or share it more easily.