- Body surface area
- 1.84 m²
How it works
Area grows slower than weight
With height fixed, a 10% increase in weight raises the Mosteller estimate by about 4.9%, not 10%. The square root explains this difference; proportional weight changes cannot be copied directly to surface-area estimates.
Comparing body surface area equations
Body surface area equations estimate an area from measurements such as height and weight. Different equations can give slightly different answers even with identical inputs. Keep the units and selected equation visible when comparing results or communicating a value. This page performs the mathematical estimate; it does not determine a medication dose or replace the method required by a clinical protocol.
Body surface area: formula and assumptions
Mosteller BSA = √[height(cm) × weight(kg) / 3600].
Body surface area is an estimate. Do not use this result to determine medication dosing without a clinician.
Eight surface-area equations: formula and assumptions
Apply the named source equation to weight in kilograms and height in centimeters, except native Schlich height in meters and Boyd weight in grams.
Equation identity, age applicability and coefficient variants matter. No averaging or medication-dose recommendation is provided. Exact area conversions follow SI definitions.
Worked example
Using the Body surface area example:
- Measurement system
- Metric (kg, cm)
- Weight (kg)
- 70
- Height (cm)
- 175
- Equation
- Mosteller
Mosteller BSA = √[height(cm) × weight(kg) / 3600].
Example result
Body surface area: 1.84 m²
These are illustrative inputs. Change the values to explore a different scenario.
Formula references
- Mosteller: simplified calculation of BSA (opens in a new tab)
- Du Bois and Du Bois (1916), original BSA article (opens in a new tab)
- Formulae for calculating body surface area in modern U.S. Army Soldiers (2020), Table 3 (opens in a new tab)
- Haycock et al. (1978), geometric BSA study in infants, children and adults (opens in a new tab)
- Gehan and George (1970), Estimation of human body surface area (opens in a new tab)
- Fujimoto et al. (1968), three age-specific formulas (opens in a new tab)
- AI-driven CT body surface area comparison (2026), published 0.007241 Takahira variant (opens in a new tab)
- Advanced Body Measurement Techniques (2024), published 0.007246 Takahira variant (opens in a new tab)
- Schlich et al. (2010), 3D body scanning and specific surface area (opens in a new tab)
- NIST SP 811 Appendix B.8 conversion factors (opens in a new tab)
References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.
Common questions
What measurements does the Mosteller formula use?
It takes height in centimeters and weight in kilograms, then calculates the square root of their product divided by 3,600.
Can I use the result to choose a medication dose?
No. Body surface area is only an estimate, and medication dosing requires clinical instructions and supervision.
Why do the eight equations give different estimates?
They were fitted to different populations and use different mathematical relationships. The named method and its study limits are part of the result; Finflo does not average them into a clinical assessment.
Prepared by Finflo. See our methodology and editorial policy. Read the relevant professional-advice limitations.