Health & Body Composition
Body Surface Area Calculator
Body surface area is the total area of your skin, a number clinicians use to dose chemotherapy and normalize kidney function. Four formulas, one result.
Body surface area (BSA) is the total skin area of the human body, estimated from height and weight using formulas such as Mosteller. It's used mainly to dose chemotherapy and adjust kidney function measurements. Results are screening estimates, not diagnoses — confirm with a clinician before acting on them.
Main use: chemotherapy dosing.
Mosteller is the clinical standard.
Typical adult BSA: 1.6–2.0 m².
Calculate Your Body Surface Area
Your Body Surface Area
What Is Body Surface Area?
Body surface area (BSA) is the total external area of the body, usually expressed in square metres. A typical adult BSA is between 1.6 and 2.0 m².
Clinicians use BSA to calculate chemotherapy doses, normalize cardiac output and glomerular filtration rate, and estimate burn areas. This calculator shows four published formulas with Mosteller as the default.
How It Is Calculated
Mosteller: BSA = √(height(cm) × weight(kg) ÷ 3600)
DuBois: BSA = 0.007184 × W^0.425 × H^0.725
Example: Example: 70 kg, 175 cm → BSA ≈ 1.84 m²
Common BSA formulas
| Formula | Equation | Notes |
|---|---|---|
| Mosteller | √(H×W/3600) | Simplest, most used |
| DuBois | 0.007184·W^0.425·H^0.725 | Historical standard |
| Haycock | 0.024265·W^0.5378·H^0.3964 | Preferred in pediatrics |
| Gehan-George | 0.0235·W^0.51456·H^0.42246 | Broadly validated |
Limitations
- Formulas can differ by up to a few percent, always use the same formula when tracking a value.
- BSA estimates are less accurate at extremes of height and weight.
- BSA isn't a health score; it has no healthy range.
Sources & Review
References used for this calculator’s formulas and thresholds:
Body Surface Area FAQ
What is normal body surface area?
Most adults fall between 1.6 and 2.0 m². Values depend on height and weight, so there's no single normal number.
Why do doctors need my BSA?
BSA is used to dose chemotherapy and other weight-based drugs, and to index cardiac output and kidney function to body size.
Which BSA formula is best?
Mosteller is the most widely used for its simplicity; Haycock is often preferred in children. Differences are small in practice.
Is BSA the same as BMI?
No. BMI is weight ÷ height² and is a screening ratio. BSA is an area estimate used for dosing and normalization.
Important disclaimer: Results are educational estimates, not a substitute for professional medical advice. Discuss your numbers with a clinician before acting on them.