Your body surface area, four formulas at once.
Enter your weight and height and see your body surface area (BSA) instantly, with the classic Du Bois result up front and the Mosteller, Haycock and Gehan-George estimates side by side so you can see how closely they agree.
Your measurements
Your weight in pounds.
Your height in centimeters (1 inch = 2.54 cm).
Weight is converted to kilograms internally (1 lb = 0.45359237 kg). The headline uses the Du Bois formula: BSA = 0.007184 x kg^0.425 x cm^0.725. Results update as you type.
What your BSA means
How the four formulas compare
Reference points on the BSA scale
Weight vs BSA at your height
Every row uses your height and the Du Bois formula. The highlighted row is the closest to your current weight.
| Weight | BSA (Du Bois) | BSA (Mosteller) | vs 1.7 m² average |
|---|
Body surface area, explained
What is Body Surface Area?
Body Surface Area (BSA) is the measured or calculated surface area of a human body, expressed in square meters (m²). Average adult BSA is approximately 1.7 m². BSA is used in medicine to calculate drug dosages (especially chemotherapy), determine cardiac output, and assess burn severity.
Du Bois vs Mosteller Formula
The Du Bois formula (1916) is: BSA = 0.007184 × weight(kg)^0.425 × height(cm)^0.725. The Mosteller formula (1987) is simpler: BSA = √(height(cm) × weight(kg) / 3600). Both produce similar results, with the Mosteller formula being preferred in many clinical settings for its simplicity.
Medical Applications of BSA
BSA is primarily used in oncology to calculate chemotherapy dosages, as drug clearance correlates better with BSA than body weight alone. It is also used to calculate glomerular filtration rate (kidney function), cardiac index, and fluid resuscitation formulas for burn patients (Parkland formula).
BSA in Fitness and Sports
In sports science, BSA is used to calculate metabolic rate more accurately, assess thermoregulation capacity (larger surface area means more heat dissipation), and normalize physiological measurements across different body sizes for fair comparison between athletes.
Common questions
What is a normal body surface area?
The average BSA for adult men is approximately 1.9 m² and for adult women is approximately 1.6 m². BSA ranges from about 1.2 m² for small adults to 2.5 m² or more for very large individuals. Newborns have a BSA of about 0.25 m².
Why is BSA used instead of weight for drug dosing?
BSA correlates more closely with metabolic rate and organ function than body weight alone. Drug clearance by the liver and kidneys relates better to BSA. This makes BSA-based dosing more accurate, especially for drugs with narrow therapeutic windows like chemotherapy agents.
How do I convert my height to centimeters?
Multiply your height in inches by 2.54 to get centimeters. For example, 5'10" = 70 inches × 2.54 = 177.8 cm. You can also use the conversion: feet × 30.48 + inches × 2.54.
Which BSA formula is more accurate?
Both formulas are clinically validated and produce similar results (typically within 0.02 m²). The Du Bois formula is the historical standard, while the Mosteller formula is newer and simpler to calculate. Most clinical guidelines accept either formula.
This calculator is for education and general fitness use only. Body surface area is used clinically to dose medications such as chemotherapy, and any BSA value used for drug dosing must be calculated, verified and prescribed exclusively by a doctor or pharmacist. Never use this page to compute, check or adjust a medication dose. If your result feeds into any medical decision, confirm it with a qualified health professional first.