BSA Calculator — Body Surface Area (Mosteller, DuBois, Haycock)
Calculate body surface area using Mosteller, DuBois, and Haycock formulas side by side. Includes an optional mg/m² dosing reference field.
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Full bio →Uses the Mosteller BSA value. For reference only — always follow your prescriber's exact dosing calculation.
Mosteller: √((height cm × weight kg) ÷ 3600). DuBois: 0.007184 × height^0.725 × weight^0.425. Haycock: 0.024265 × height^0.3964 × weight^0.5378. Formulas typically agree within 1-2% for average adult body sizes but can diverge more at pediatric or larger body sizes. This tool is for reference and educational purposes — actual medication dosing must be calculated and verified by a qualified healthcare provider, not derived solely from this calculator.
Reference Values
Last verified:| Category | Range | What It Means | Status |
|---|---|---|---|
| Mosteller Formula ★ | √((height cm × weight kg) ÷ 3600) | The most widely used formula in clinical practice — simple, well-validated, and the preferred standard for chemotherapy dosing. | ★ Best |
| DuBois & DuBois Formula | 0.007184 × height^0.725 × weight^0.425 | The original 1916 formula, still permitted at many chemotherapy sites as long as it doesn't produce more than a 10% dosing difference from Mosteller. | Good |
| Haycock Formula | 0.024265 × height^0.3964 × weight^0.5378 | Commonly preferred in pediatric settings — performs well across smaller body sizes where adult-derived formulas can be less accurate. | Good |
| Typical Adult Range | ~1.6 m² (average female) to ~1.9 m² (average male) | Average adult BSA is often cited around 1.7 m² overall — individual results vary substantially with height and weight. | Okay |
Source: Mosteller RD (1987) NEJM; Du Bois D & Du Bois EF (1916) Arch Intern Med; Haycock GB et al. (1978) J Pediatr — standard clinical BSA formulas
Worked Examples
Average Adult — 170 cm, 70 kg
- Height
- 170 cm
- Weight
- 70 kg
All three formulas agree closely (within 1%) for typical adult proportions — this is the normal case where formula choice matters least.
Child — 150 cm, 25 kg
- Height
- 150 cm
- Weight
- 25 kg
The formulas diverge more at smaller body sizes — a roughly 7% spread between DuBois and Haycock here, which is why Haycock is often preferred in pediatric dosing.
Larger Adult — 180 cm, 95 kg
- Height
- 180 cm
- Weight
- 95 kg
Above the typical 1.6–1.9 m² adult range — at higher body sizes, formula choice can shift a chemotherapy dose calculation by a meaningful amount, which is why sites cap acceptable formula disagreement at 10%.
How to Use This Calculator
- 1
Choose units and enter height and weight
Metric (cm/kg) or imperial (ft-in/lb) — whichever matches your available measurements.
- 2
Read all three formula results at once
Mosteller, DuBois & DuBois, and Haycock are calculated simultaneously so you can compare them directly.
- 3
Optionally add a dose-per-m² reference value
See a reference total dose based on the Mosteller BSA value — for educational reference only, not a substitute for prescriber-calculated dosing.
What Each Value Means
- Body Surface Area (BSA) (m²)
- An estimate of the total surface area of the human body, calculated from height and weight, used to scale medication doses and other clinical measures more precisely than body weight alone.
- Mosteller Formula (m²)
- BSA = √((height cm × weight kg) ÷ 3600). The most commonly used clinical BSA formula, preferred for its simplicity and validation in chemotherapy dosing.
- DuBois & DuBois Formula (m²)
- BSA = 0.007184 × height^0.725 × weight^0.425. The original 1916 BSA formula, still in clinical use today.
- Haycock Formula (m²)
- BSA = 0.024265 × height^0.3964 × weight^0.5378. Often preferred in pediatric dosing calculations.