medical-pharmaceutical
Body Surface Area (BSA) Calculator
Calculate body surface area using different formulas for medical dosing and clinical assessments.
Reviewed by the calculator.uk.com Team · Last reviewed 23 May 2026 · Our methodology
Enter height and weight to calculate BSA
Related to Body Surface Area (BSA) Calculator
The Body Surface Area (BSA) Calculator determines the total surface area of the human body using various validated formulas. BSA is a crucial measurement in medicine, particularly for determining drug dosages, assessing metabolic rates, and evaluating cardiac function. Our calculator offers three widely-accepted formulas: DuBois, Mosteller, and Haycock.
Available Formulas
1. DuBois Formula (1916): The most widely used formula, particularly accurate for average adult body types.
2. Mosteller Formula (1987): A simplified formula that's easier to calculate and remember.
3. Haycock Formula (1978): Particularly accurate for infants and children.
Calculation Method
Each formula uses height (in centimeters) and weight (in kilograms) to calculate BSA in square meters (m²). The calculator automatically applies the mathematical formulas and provides results to two decimal places for precision in medical applications.
Body Surface Area results are typically used in medical settings for various purposes. Understanding how to interpret and use these results is crucial for healthcare professionals and researchers.
Normal BSA Ranges
• Average adult male: 1.9 m² (range: 1.7-2.2 m²)
• Average adult female: 1.6 m² (range: 1.4-1.8 m²)
• Children: Varies significantly with age and size
Common Applications
• Drug Dosing: Many medications are dosed based on BSA
• Cardiac Index: Heart function measurements are indexed to BSA
• Metabolic Rate: BSA is used to standardize metabolic measurements
• Burns Assessment: Calculating the extent of burns as a percentage of BSA
1. Which BSA formula should I use?
The DuBois formula is most commonly used in clinical practice and research. However, the Mosteller formula is simpler and nearly as accurate. For pediatric patients, the Haycock formula may be more appropriate. When in doubt, consult with a healthcare provider about which formula is most appropriate for your specific situation.
2. How accurate are BSA calculations?
BSA calculations are generally accurate within 3-5% when using any of the standard formulas. The main source of error typically comes from inaccurate height or weight measurements rather than the formulas themselves.
3. Why is BSA used instead of body weight for drug dosing?
BSA correlates better with physiological functions like blood volume, cardiac output, and metabolic rate than body weight alone. This makes it a more reliable basis for drug dosing, especially for medications with narrow therapeutic windows like chemotherapy drugs.
4. Can BSA be used for children and infants?
Yes, BSA can be calculated for children and infants. The Haycock formula is particularly accurate for smaller body sizes. However, pediatric dosing often requires additional considerations beyond BSA alone.
5. What is the scientific source for this calculator?
BSA here is calculated with three formulas that have each been standard in medicine for decades: the DuBois and DuBois height-weight equation published in 1916, the simplified square-root formula Mosteller described in 1987, and the Haycock formula from 1978, which was derived specifically from pediatric measurements. All three remain widely cited and used in clinical dosing calculations today, with DuBois still the most common default in adult practice and Haycock generally preferred for infants and children.