BSA Calculator
Created by: James Porter Medical Calculator Specialist
Last updated:
Reviewed by the Complete Calculators Editorial Team
Professional Body Surface Area (BSA) calculator using validated medical formulas including Du Bois, Mosteller, and Haycock methods. This specialized tool provides accurate BSA calculations essential for chemotherapy dosing, cardiac assessments, burn treatment, and pediatric medicine with comprehensive clinical reference content.
Body Surface Area (BSA) Calculator
Calculate Body Surface Area using validated medical formulas. Essential for chemotherapy dosing, cardiac assessments, and clinical calculations.
Select BSA Formula
Enter your height
Enter your weight
BSA Reference Ranges
Adult Ranges:
- • Small adult: 1.5-1.7 m²
- • Average adult: 1.7-2.0 m²
- • Large adult: 2.0-2.5 m²
Pediatric Ranges:
- • Newborn: ~0.25 m²
- • 1 year: ~0.5 m²
- • 10 years: ~1.14 m²
What is Body Surface Area (BSA)?
Body Surface Area (BSA) is a critical physiological measurement representing the total surface area of the human body, typically expressed in square meters (m²). BSA calculations are fundamental in medical practice, particularly for determining appropriate drug dosages, assessing cardiac function, and evaluating metabolic parameters.
Unlike simple body weight measurements, BSA accounts for both height and weight, providing a more accurate representation of physiological function. This measurement correlates strongly with metabolic rate, organ function, and drug clearance, making it essential for personalized medical treatment and pharmaceutical calculations.
Medical professionals use BSA calculations daily for chemotherapy dosing, cardiac index determination, burn assessment, and pediatric medicine. The precision of BSA calculations can literally be life-saving, as many potent medications require dosing based on surface area rather than weight to ensure both safety and efficacy.
How BSA Calculation Works
BSA calculations use mathematical formulas that correlate height and weight measurements to estimate total body surface area. Several validated formulas exist, each with specific advantages for different patient populations and clinical applications.
Primary BSA Formulas
Most widely accepted clinical standard
Simplified and highly accurate
Example Calculation
Scenario: Adult male, 180 cm tall, 75 kg weight
Du Bois Formula: 0.007184 × 75^0.425 × 180^0.725
Result: 1.96 m² BSA
Medical Applications
BSA calculations serve essential functions across numerous medical specialties, from oncology to cardiology, providing the foundation for personalized treatment protocols and safety guidelines.
Oncology and Chemotherapy
- • Chemotherapy drug dosing calculations
- • Radiation therapy treatment planning
- • Toxicity assessment and monitoring
- • Clinical trial enrollment criteria
Cardiology and Critical Care
- • Cardiac index calculations
- • Hemodynamic assessments
- • Dialysis and fluid management
- • Burn area assessment and treatment
Advanced BSA Concepts
Formula Selection in Clinical Practice
Different clinical situations may favor specific BSA formulas. The Du Bois formula remains the gold standard for adult populations, while the Haycock formula shows superior accuracy in pediatric patients. The Mosteller formula offers computational simplicity while maintaining clinical accuracy, making it popular in emergency settings.
Population-Specific Considerations
BSA calculations may require adjustment for specific populations. Obese patients may have overestimated BSA using standard formulas, while very tall or muscular individuals may need specialized considerations. Pediatric applications require age-appropriate formulas and careful attention to developmental changes in body proportions.
Clinical Considerations
- • BSA calculations assume normal body proportions
- • Extreme obesity may require adjusted formulas
- • Pediatric patients need age-appropriate calculations
- • Always verify calculations for high-risk medications
Frequently Asked Questions
What is Body Surface Area (BSA) and why is it important?
Body Surface Area (BSA) is a measurement of the total surface area of the human body, typically expressed in square meters (m²). BSA is crucial in medicine for calculating drug dosages, determining cardiac index, assessing metabolic rate, and planning medical treatments. It provides a more accurate basis than body weight alone for many physiological calculations.
Which BSA formula is most accurate?
The Du Bois formula is the most widely used and accepted standard in clinical practice, developed in 1916 and still considered the gold standard. The Mosteller formula is simpler and also highly accurate, while Haycock is preferred for pediatric patients. Our calculator uses the Du Bois formula as the primary method with other formulas available for comparison.
How is BSA used in medical dosing calculations?
Many medications, especially chemotherapy drugs, are dosed based on BSA rather than body weight because BSA correlates better with metabolic rate and organ function. For example, a drug might be prescribed at 100 mg/m² of BSA. If a patient has a BSA of 1.8 m², their dose would be 180 mg (100 × 1.8).
What is the normal range for BSA in adults?
For adults, normal BSA typically ranges from 1.5 to 2.0 m². Average adult males have a BSA around 1.9 m², while average adult females have approximately 1.6 m². Very large individuals may exceed 2.5 m², while smaller adults may be below 1.5 m². BSA varies significantly with height and weight.
Can I use BSA calculations for children and infants?
Yes, BSA calculations are especially important in pediatric medicine for accurate drug dosing. However, the normal ranges are much lower: newborns have a BSA around 0.25 m², one-year-olds approximately 0.5 m², and ten-year-olds about 1.14 m². The Haycock formula is often preferred for pediatric patients.
How accurate are BSA calculations compared to direct measurement?
Mathematical BSA formulas are highly accurate, typically within 5% of direct measurements using advanced imaging techniques. The Du Bois and Mosteller formulas show the best correlation with actual surface area measurements. These calculations are considered clinically reliable for all medical applications.
Why don't we just use body weight for medical calculations?
Body weight alone doesn't account for height and body composition differences. Two people with the same weight but different heights have very different surface areas and metabolic rates. BSA provides a more accurate assessment of physiological function, making it essential for chemotherapy dosing, cardiac output calculations, and metabolic studies.
Should I use metric or imperial units for BSA calculations?
Both metric and imperial units can be used for BSA calculations, as our calculator automatically converts between systems. However, medical literature typically reports BSA in square meters (m²), so results are standardized regardless of input units. Height in centimeters and weight in kilograms are most common in clinical settings.
Sources and References
- Du Bois D, Du Bois EF. "A formula to estimate the approximate surface area if height and weight be known." Archives of Internal Medicine. 1916;17(6):863-71.
- Mosteller RD. "Simplified calculation of body-surface area." New England Journal of Medicine. 1987;317(17):1098.
- Haycock GB, Schwartz GJ, Wisotsky DH. "Geometric method for measuring body surface area: a height-weight formula validated in infants, children, and adults." Journal of Pediatrics. 1978;93(1):62-66.
- Gehan EA, George SL. "Estimation of human body surface area from height and weight." Cancer Chemotherapy Reports. 1970;54(4):225-35.
- National Cancer Institute. "Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0." 2017.
- American Society of Clinical Oncology. "Clinical Practice Guidelines for Chemotherapy Dosing." Journal of Clinical Oncology. 2019.
- European Medicines Agency. "Guideline on the clinical investigation of the pharmacokinetics of therapeutic proteins." 2018.
- World Health Organization Expert Committee. "Physical Status: The Use and Interpretation of Anthropometry." Technical Report Series 854, 1995.