Body Surface Area Calculator
Calculate your body surface area (BSA) using the Du Bois and Mosteller formulas. BSA is an important measurement used in clinical medicine, pharmacology, and physiological assessments.
How This Calculator Works
Formula: Du Bois and Mosteller Formulas
The Du Bois formula (1916) calculates BSA as 0.007184 x height(cm)^0.725 x weight(kg)^0.425. The Mosteller formula (1987) provides a simplified calculation: the square root of (height(cm) x weight(kg) / 3600). Both formulas use height and weight to estimate the total surface area of the body in square meters. The average adult BSA is approximately 1.7 m².
Limitations
- BSA formulas were developed from limited population samples and may be less accurate for individuals at extremes of body size.
- These formulas assume typical body proportions and may be less accurate for amputees or individuals with atypical limb proportions.
- The Du Bois formula was originally developed from a small sample of only 9 subjects.
- Neither formula accounts for body composition differences between individuals of the same height and weight.
These calculations are estimates based on established formulas. Individual results vary. Consult a healthcare professional before making significant changes to your diet or exercise routine.
Body surface area (BSA) measures the total area of the external surface of the human body. While it may seem like an unusual metric for fitness, BSA has important applications in medicine, pharmacology, and exercise physiology.
In clinical settings, BSA is commonly used to calculate drug dosages, particularly for chemotherapy agents, where dosing based on surface area provides better results than dosing by weight alone. BSA is also used in cardiology to index cardiac output and in nephrology to standardize kidney function measurements.
This calculator implements two widely used formulas. The Du Bois formula, developed in 1916, is the oldest and most referenced BSA equation. Despite its age and small original sample size, it remains a standard in clinical practice. The Mosteller formula, introduced in 1987, offers a simplified calculation that produces results very close to the Du Bois method.
For most adults, BSA falls between 1.5 and 2.2 square meters, with an average of approximately 1.7 m². BSA correlates with metabolic rate and is sometimes used as an alternative to body weight for normalizing physiological measurements across individuals of different sizes.
While BSA is primarily a clinical tool, understanding your body surface area can be useful for interpreting medical test results, understanding heat dissipation during exercise, and contextualizing hydration needs. Larger surface areas generally mean greater heat loss and potentially higher fluid requirements during exercise in hot environments.