Body Surface Area Calculator
Calculate your Body Surface Area (BSA) using multiple medical formulas. BSA is used in medical dosing, cardiac index calculations, and metabolic assessments.
Patient Information
Quick Presets
BSA Results
All Formula Results
Statistical Analysis
Clinical Applications
Age-Based Normal Ranges
Clinical Notes
- • Du Bois formula is most widely used in clinical practice
- • Mosteller formula is simpler and often preferred for quick calculations
- • Haycock formula is recommended for pediatric patients
- • BSA is used for drug dosing, cardiac output indexing, and burn assessment
How BSA Calculation Works
What is Body Surface Area?
Body Surface Area (BSA) is the measured or calculated surface area of a human body. It's expressed in square meters (m²) and is used in many medical calculations including drug dosing, cardiac output indexing, and metabolic assessments.
Clinical Importance
- Drug Dosing: Many medications are dosed per m² of BSA
- Cardiac Index: Cardiac output normalized to BSA
- Burn Assessment: Burn severity as % of BSA
- Metabolic Studies: Normalizing metabolic rates
Common Formulas
Du Bois & Du Bois (1916)
BSA = 0.007184 × W^0.425 × H^0.725
Most widely used in clinical practice
Mosteller (1987)
BSA = √(H × W / 3600)
Simplified formula, easy to calculate
Haycock (1978)
BSA = 0.024265 × W^0.5378 × H^0.3964
Recommended for pediatric patients
How to Use This Calculator
Step-by-Step Guide
- 1. Enter patient's age and gender
- 2. Input accurate height and weight measurements
- 3. Select appropriate formula for your use case
- 4. Review the calculated BSA result
- 5. Compare with other formulas if needed
- 6. Use BSA for clinical calculations as required
Formula Selection Guide
- Du Bois: General clinical use, most validated
- Mosteller: Quick calculations, emergency settings
- Haycock: Pediatric patients (preferred)
- Gehan & George: Alternative for adults
- Fujimoto: Asian populations
- Boyd: Research applications
Example Calculation
Sample Patient
- Age: 35 years
- Gender: Male
- Height: 175 cm
- Weight: 70 kg
- Formula: Du Bois & Du Bois
Calculation Steps
- 1. BSA = 0.007184 × W^0.425 × H^0.725
- 2. BSA = 0.007184 × 70^0.425 × 175^0.725
- 3. BSA = 0.007184 × 5.477 × 31.89
- 4. BSA = 1.85 m²
Frequently Asked Questions
Which BSA formula is most accurate?
The Du Bois & Du Bois formula is most widely validated and used in clinical practice. For pediatric patients, the Haycock formula is often preferred. The choice depends on your specific application and patient population.
Why is BSA used instead of body weight for drug dosing?
BSA correlates better with many physiological processes including cardiac output, glomerular filtration rate, and metabolic rate. This makes it more accurate for dosing medications, especially chemotherapy drugs.
What is the average BSA for adults?
The average BSA for adults is approximately 1.7 m² (range 1.6-1.9 m²). This value is often used as a standard reference in medical calculations and research.