What is a normal BSA for adults?

Average adult BSA is approximately 1.7-2.0 m². Men average around 1.9 m² and women around 1.6 m². These values vary with height and weight.

Which BSA formula is most accurate?

All three formulas produce very similar results for typical adult sizes. Du Bois is the most historically cited, while Mosteller is the simplest to calculate. Haycock may be preferred for broader populations.

What is BSA used for in fitness?

In fitness contexts, BSA helps normalize metabolic rate measurements and understand thermoregulation differences between individuals of different sizes.

How is BSA different from BMI?

BMI is a ratio of weight to height squared, while BSA estimates actual skin surface area. BSA uses different mathematical exponents and produces a result in square meters rather than a dimensionless ratio.

BSA Calculator

Name: BSA Calculator
Author: Manish Kumar

What Is Body Surface Area?

Body Surface Area (BSA) is an estimate of the total area of your body's outer surface, measured in square meters (m²). It is calculated from height and weight using validated mathematical formulas ^[1].

The average adult BSA falls between 1.7 and 2.0 m². BSA provides a size-normalized measurement that can be useful for comparing metabolic rates and understanding thermoregulation across individuals of different sizes.

The Three Formulas

Du Bois & Du Bois (1916): The original and most widely cited formula. Uses height and weight exponents derived from early measurements ^[2]
Mosteller (1987): A simplified formula that produces very similar results. Calculated as √((height × weight) / 3600) ^[1]
Haycock (1978): Developed with a broader sample including children and adults, using different exponents for height and weight ^[3]

All three formulas generally agree within 2–5% for typical adult body sizes. Differences may be larger at extreme heights or weights.

BSA in Fitness Contexts

In fitness and exercise science, BSA is used to normalize metabolic rate measurements. Individuals with larger BSA relative to body mass tend to dissipate heat more efficiently, which can be relevant for endurance activities in warm environments.

For other body measurement tools, explore our Lean Body Mass Calculator and Body Measurements Tracker.

How to Use This Calculator

Choose your unit system (imperial or metric)
Enter your height and weight
Click "Calculate BSA" to see results from all three formulas
Compare the formula results and review the average

Frequently Asked Questions

Sources & References

Body Surface Area: Estimation and Applications. Verbraecken J, et al.. StatPearls (NCBI) (2023)
Determination of Body Surface Area and Formulas Using the Alginate Method. Yu CY, et al.. ResearchGate Publication (2008)
Body Surface Area Estimation: Validation and Comparison of Formulas. Multiple authors. PMC Research Article (2024)

Disclaimer: This calculator is for informational and personal awareness purposes only. Results are estimates based on published formulas and may not reflect your exact measurements or outcomes.

Manish KumarNASM-CPTCertified Sports Nutritionist

Certified Personal Trainer & Sports Nutritionist

Fitness professional with 10+ years of experience in personal training, sports nutrition, and fitness technology.

Body Surface Area (BSA) Calculator