Body Surface Area Calculator
Calculate your body surface area (BSA) using different medical formulas. Accurate BSA calculator for healthcare professionals and patients.
BSA Calculator
Calculating your body surface area…
BSA Calculation Results
Formula Comparison
See how different formulas calculate BSA for the same height and weight
| Formula | BSA (m²) | BSA (ft²) |
|---|
About Body Surface Area
Body Surface Area (BSA) is the measured or calculated surface area of a human body. It is used in many medical tasks, such as determining dosages for medications and calculating fluid resuscitation needs.
Why is BSA Important?
BSA is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass. It’s particularly important for:
- Calculating chemotherapy dosages
- Determining glucocorticoid dosages
- Assessing burn severity
- Calculating cardiac index
- Estimating renal function
Common BSA Formulas
Several formulas have been developed over the years to estimate BSA. The most commonly used include:
Du Bois Formula (1916): The most widely used formula, developed by Du Bois and Du Bois.
Mosteller Formula (1987): A simplified formula that’s easy to calculate and remember.
Haycock Formula (1978): Developed specifically for pediatric patients.
Gehan & George Formula (1970): Based on a study of 401 subjects.
Boyd Formula (1935): One of the earliest formulas, based on height and weight.
Fujimoto Formula (1968): Developed for Japanese subjects.
Takahira Formula (1925): An early formula developed for Japanese subjects.
Frequently Asked Questions
The average body surface area for adults is approximately 1.7 m² (18.3 ft²) for men and 1.6 m² (17.2 ft²) for women. However, BSA varies significantly based on height, weight, age, and gender.
There is no single “most accurate” BSA formula. Different formulas may be more appropriate for different populations. The Du Bois formula is the most widely used in clinical practice, while the Mosteller formula is preferred for its simplicity. For pediatric patients, the Haycock formula is often recommended.
Many medications, especially chemotherapy drugs, are dosed based on BSA rather than body weight. This is because BSA better correlates with metabolic processes and organ function. The dosage is typically calculated as mg/m² of BSA.
BSA increases rapidly during childhood and adolescence, peaks in early adulthood, and gradually decreases in older age. Newborns have an average BSA of about 0.25 m², while adults typically range from 1.5 to 2.0 m².
While BSA alone is not a comprehensive indicator of nutritional status, it can be used in combination with other measures. Abnormally low BSA relative to height and weight may indicate malnutrition or muscle wasting.