Last updated October 13, 2026 · Report an error
Body Surface Area (BSA) estimates the total surface area of the human body, and is used clinically for tasks like calculating medication dosing (particularly chemotherapy) more precisely than weight alone allows.
This calculator uses the Mosteller formula, valued for its simplicity relative to the older, more complex DuBois formula, while remaining widely accepted in clinical use.
How it works
Enter height and weight. The tool applies the Mosteller formula — the square root of (height in cm × weight in kg, divided by 3600) — to estimate BSA in square meters.
- Enter height (cm).
- Enter weight (kg).
- Click Calculate to see your results.
Examples
BSA for an average adult
A 175cm, 70kg adult has an estimated BSA of about 1.84 m².
Who should use it
- General informational estimate of body surface area.
- Understanding what BSA-based medical dosing references mean.
Industry applications
- Healthcare and clinical reference
- Medical and nursing education
Advantages
- Uses a well-established, clinically-recognized formula.
- Simple two-input calculation.
Limitations
- Not a substitute for a healthcare provider's clinical dosing calculation.
Common mistakes to avoid
- Using this as a substitute for a healthcare provider's dosing calculation.
- Confusing BSA (a surface area measure) with BMI (a weight-to-height ratio) — they measure different things entirely.
Best practices
- Treat this as a general estimate for informational purposes, not a substitute for a healthcare provider's clinical calculation.
Tips
- If you're researching BSA in a medical context, always confirm actual dosing calculations with a qualified healthcare provider rather than relying on a self-service tool.
Frequently asked questions
Yes, with no signup and no limit on how many calculations you run.
BSA correlates better than weight alone with several physiological factors (like blood volume and metabolic rate) that affect how a drug distributes through the body, which is why some medications are dosed per BSA.
No — the DuBois formula is another widely used method; Mosteller is simpler to calculate and produces very similar results for most adults, which is why it's commonly preferred.
No — this tool is for general informational purposes. Actual medication dosing must be determined by a qualified healthcare provider, not a self-service calculator.