Body Surface Area
Calculate BSA using multiple medical formulas
These calculators provide general information only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.
How to use Body Surface Area
- 1Enter your height and weight.
- 2Pick a formula such as Du Bois, Mosteller, or Haycock if available.
- 3Read your BSA in square metres, used for medical dosing.
Why body surface area matters
Mosteller: BSA = sqrt( (height cm x weight kg) / 3600 )BSA estimates the total skin area and is used to dose certain drugs, especially chemotherapy, because it scales better than weight alone.
Different formulas give slightly different results; clinicians pick one consistently. Never adjust prescribed doses yourself.
Frequently asked questions
Why use BSA instead of weight?
Many physiological processes scale with surface area, so BSA gives more consistent dosing across body sizes.
Which formula is best?
They agree closely for average adults; Mosteller is common for its simplicity, Du Bois is a long-standing standard.
Can I use BSA to change my medication?
Never. BSA guides prescribers; do not alter prescribed doses without your clinician.