Body Surface Area Calculator
Advanced BSA Calculator with Multiple Formulas
BSA Calculator
Calculating your BSA…
Understanding Body Surface Area
What is Body Surface Area?
Body Surface Area (BSA) is a measurement of the total surface area of the human body. It’s expressed in square meters (m²) and is crucial for various medical calculations including drug dosing, cardiac index, and metabolic assessments.
BSA provides a more accurate representation of metabolic mass than body weight alone, making it essential for:
- Chemotherapy drug dosing
- Cardiac output calculations
- Burn treatment planning
- Nutritional assessments
BSA Calculation Formulas
DuBois Formula (1916): The most widely used formula in clinical practice. Provides reliable results for adults and children.
Mosteller Formula (1987): Simplified calculation that’s easier to remember and calculate manually. Widely accepted in medical practice.
Haycock Formula (1978): Particularly accurate for pediatric patients and smaller body sizes.
Gehan & George Formula (1970): Good for a wide range of body sizes, from infants to adults.
Boyd Formula (1935): More complex but highly accurate, especially for extreme body sizes.
Medical Applications
BSA is fundamental in healthcare for precise medical calculations:
- Oncology: Chemotherapy dosing based on BSA reduces toxicity while maintaining efficacy
- Cardiology: Cardiac index calculation (cardiac output/BSA) for heart function assessment
- Nephrology: Glomerular filtration rate normalization
- Burn Medicine: Fluid resuscitation calculations for burn patients
- Pediatrics: Age-appropriate medication dosing
- Anesthesia: Drug dosing for surgical procedures
Normal BSA Ranges
Understanding typical BSA values helps interpret results:
- Adult Males: 1.9 – 2.2 m² (average: 2.0 m²)
- Adult Females: 1.6 – 1.9 m² (average: 1.7 m²)
- Children (10 years): ~1.14 m²
- Children (5 years): ~0.76 m²
- Infants (1 year): ~0.47 m²
- Newborns: ~0.25 m²
These ranges vary based on height, weight, age, and individual body composition.
BSA Calculation Tips & Guidelines
Accurate Measurements
Use precise height and weight measurements. Remove shoes for height and use a calibrated scale for weight. Morning measurements are typically most consistent.
Choose the Right Formula
DuBois is most common for adults, Mosteller for quick calculations, and Haycock for pediatric patients. Consult healthcare providers for medical applications.
Unit Consistency
Ensure consistent units throughout calculations. Our calculator handles conversions automatically, but manual calculations require careful unit management.
Age Considerations
Different formulas may be more appropriate for different age groups. Haycock formula is preferred for children, while DuBois works well for adults.
Medical Context
BSA calculations for medical purposes should always be verified by healthcare professionals. This tool is for educational and reference purposes.
Regular Monitoring
BSA changes with weight and height variations. Regular recalculation may be necessary for ongoing medical treatments or fitness tracking.
Frequently Asked Questions
The DuBois formula is considered the gold standard and most widely used in clinical practice. However, the “most accurate” depends on the specific population and use case:
DuBois: Best overall accuracy for general adult population
Mosteller: Good accuracy with simpler calculation
Haycock: Most accurate for pediatric patients
Boyd: Highest accuracy for extreme body sizes
BSA is crucial in medicine because it provides a more accurate basis for dosing medications than body weight alone. It correlates better with metabolic rate, organ size, and physiological functions.
Key medical applications include:
- Chemotherapy dosing to minimize toxicity
- Cardiac output normalization (cardiac index)
- Burn treatment fluid calculations
- Pediatric medication dosing
- Anesthesia drug calculations
BSA should be recalculated whenever there are significant changes in height or weight:
For medical treatments: Before each treatment cycle or as directed by healthcare providers
For growing children: Every 3-6 months or during routine check-ups
For adults: When weight changes by more than 5-10% or annually for health monitoring
For fitness tracking: Monthly or quarterly assessments
Yes, BSA can be useful for fitness and nutrition, though it’s not the only metric to consider:
Metabolic Rate: BSA correlates with basal metabolic rate better than weight alone
Calorie Needs: Can help estimate daily caloric requirements
Supplement Dosing: Some supplements use BSA-based dosing
Training Load: Can help normalize training intensity across different body sizes
However, body composition, activity level, and individual metabolism are also important factors.
Different BSA formulas were developed for specific populations and use cases:
DuBois (1916): Based on 9 subjects, widely validated, most commonly used
Mosteller (1987): Simplified for easy calculation, good correlation with DuBois
Haycock (1978): Based on 81 subjects, excellent for children and small adults
Gehan & George (1970): Based on 401 subjects, good for wide range of sizes
Boyd (1935): Complex formula, very accurate for extreme body sizes
The differences are usually small (within 5%) for typical adult sizes.
This calculator is designed for educational and reference purposes. While it uses medically accepted formulas, it should not replace professional medical advice or calculations.
For medical treatments: Always verify calculations with healthcare providers
For drug dosing: Use hospital-approved calculators and protocols
For research: Consider the specific requirements of your study
For general health: This tool provides reliable estimates for personal reference
Always consult healthcare professionals for medical applications of BSA calculations.
