Body Surface Area Calculator
Calculate your body surface area (BSA) using the Mosteller formula and other methods. BSA is used for drug dosing, burn assessment, and other medical applications.
Calculate Your Body Surface Area
Enter your weight and height to calculate your body surface area using multiple formulas.
Understanding Body Surface Area
Body surface area (BSA) is a calculated measurement of the total surface area of the human body. Unlike weight or height alone, BSA provides a more accurate reflection of metabolic mass because it takes both height and weight into account.
BSA is widely used in medicine for various purposes:
- Drug Dosing: Many medications, especially chemotherapy drugs, are dosed based on BSA to optimize efficacy while minimizing toxicity.
- Burn Assessment: The "rule of nines" and other methods use BSA to estimate the extent of burns.
- Cardiac Function: Cardiac output is often indexed to BSA to calculate the cardiac index.
- Renal Function: Glomerular filtration rate (GFR) can be adjusted for BSA.
- Fluid Requirements: BSA can help determine fluid needs, especially in pediatric patients.
Several formulas have been developed to calculate BSA:
- Mosteller Formula (1987): The most widely used due to its simplicity and reasonable accuracy. BSA (m²) = √[(Height (cm) × Weight (kg)) ÷ 3600]
- Du Bois & Du Bois Formula (1916): One of the earliest formulas, still widely used. BSA (m²) = 0.007184 × Height (cm)^0.725 × Weight (kg)^0.425
- Haycock Formula (1978): Often preferred for pediatric patients. BSA (m²) = 0.024265 × Height (cm)^0.3964 × Weight (kg)^0.5378
- Gehan & George Formula (1970): Another alternative method. BSA (m²) = 0.0235 × Height (cm)^0.42246 × Weight (kg)^0.51456
- Boyd Formula (1935): A more complex formula that some consider more accurate for certain populations. BSA (m²) = 0.0003207 × Height (cm)^0.3 × Weight (g)^(0.7285 - 0.0188 × log(Weight (g)))
For most adults, BSA typically ranges from 1.2 to 2.5 m², with an average of about 1.7 m² (1.9 m² for men, 1.6 m² for women). However, these values can vary significantly based on height, weight, and body composition.
Frequently Asked Questions
- What is body surface area?
Body surface area (BSA) is the measured or calculated surface area of the human body. It's used in many medical contexts, including drug dosage calculations, burn assessment, and cardiac output measurements.
- How is body surface area calculated?
This calculator uses the Mosteller formula: BSA (m²) = √[(Height (cm) × Weight (kg)) ÷ 3600]. There are also other formulas like Du Bois & Du Bois and Haycock that give slightly different results.
- Why is body surface area important?
BSA is important in medicine for determining drug dosages (especially for chemotherapy), calculating cardiac index, estimating renal function, and determining fluid requirements. It provides a more accurate basis for these calculations than body weight alone.
- What is a normal body surface area?
The average adult has a BSA of about 1.7 m² (1.9 m² for men, 1.6 m² for women). However, "normal" varies widely based on height and weight. BSA typically ranges from 1.2 to 2.5 m² in adults.
- Which BSA formula is most accurate?
No single formula is universally accepted as the most accurate. The Mosteller formula is widely used due to its simplicity and reasonable accuracy. For specific medical applications, healthcare providers may prefer certain formulas based on the patient population.