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Calculate BSA for medical dosing and clinical applications
Body Surface Area (BSA) is the measured or calculated surface area of the human body. It's used in medical settings for drug dosing, cardiac index calculation, and burn assessment.
Enter your details to calculate body surface area
Most widely used in clinical practice.
BSA = 0.007184 × W^0.425 × H^0.725
Simplest and highly accurate, recommended by many.
BSA = √[(W × H) / 3600]
Particularly accurate for children and infants.
BSA = 0.024265 × W^0.5378 × H^0.3964
Validated across wide range of ages and sizes.
BSA = 0.0235 × W^0.51456 × H^0.42246
W = weight in kg, H = height in cm
Most cancer drugs are dosed based on BSA (mg/m²) to standardize treatment across different body sizes.
Cardiac output divided by BSA gives cardiac index, a normalized measure of heart function.
Burn severity and fluid resuscitation calculated using percentage of BSA affected.
Glomerular filtration rate (GFR) is normalized to BSA for comparison across patients.
Many medications use BSA-based dosing, especially in pediatrics and oncology.
Basal metabolic rate and energy expenditure normalized to BSA for research.
| Population | Average BSA (m²) | Range |
|---|---|---|
| Newborns | 0.25 | 0.20 - 0.30 |
| 2-year-old children | 0.5 | 0.45 - 0.55 |
| 10-year-old children | 1.14 | 1.00 - 1.30 |
| Adult women | 1.6 | 1.4 - 1.8 |
| Adult men | 1.9 | 1.7 - 2.1 |
BSA is primarily used in medicine for calculating drug dosages (especially chemotherapy), determining cardiac index, assessing burn severity, and normalizing physiological measurements like glomerular filtration rate.
The Mosteller formula is generally considered the most accurate and is recommended by many medical organizations due to its simplicity and validation across populations. However, all formulas provide clinically acceptable estimates.
BSA correlates better with metabolic mass and organ size than body weight alone. This makes it more reliable for dosing medications, especially in populations with varying body compositions.
No, men typically have larger BSA than women due to generally larger body size. However, the formulas don't differentiate by gender - they calculate based purely on height and weight.
Yes, BSA is commonly used in pediatrics. The Haycock formula is particularly accurate for children. Proper BSA calculation is crucial for safe medication dosing in pediatric populations.
BSA formulas may be less accurate in extremely obese individuals. Some clinicians use adjusted body weight or alternative dosing strategies for obese patients, particularly for chemotherapy.
BSA should be recalculated whenever there's significant weight change (typically 5-10% or more) or before starting new medications that are dosed based on BSA.
Average BSA for adult women is around 1.6 m² (range 1.4-1.8), and for adult men around 1.9 m² (range 1.7-2.1). Individual variation is normal and depends on height and weight.
Medical Disclaimer: This calculator provides BSA estimates for educational purposes only. Medical professionals should use validated clinical tools and consider individual patient factors when using BSA for medication dosing or medical calculations. Always consult healthcare professionals for medical decisions.