Body Surface Area Calculator
Calculate body surface area (BSA) using multiple medical formulas for accurate drug dosing, treatment planning, and clinical assessments with instant results.
Calculate Body Surface Area
Get accurate BSA results using medical formulas
Your BSA Results
Enter your details above to see personalized results
Body Surface Area
Square meters (m²)
Selected formula result
Body Mass Index
BMI reference
BMI category
Surface Area Ratio
Of average adult BSA (1.73 m²)
Dosing Index
Relative to standard adult dose
Formula Comparison
Du Bois
Classic formula
Mosteller
Recommended
Boyd
Alternative
Haycock
Pediatric
Note: Different formulas may yield slightly different results. The Mosteller formula is widely recommended for clinical use due to its simplicity and accuracy.
Clinical Reference Ranges
Awaiting Your Calculation
Complete the form above to see clinical reference ranges, medical applications, and dosing guidelines specific to your calculated BSA value.
Clinical Applications
- Chemotherapy drug dosing calculations
- Cardiac output and index assessments
- Burn injury severity evaluation
- Renal function normalization
Medical Note: BSA calculations are for informational purposes only. Always consult healthcare professionals for medical decisions and drug dosing protocols.
Expert Medical Tips
Drug Dosing Accuracy
BSA-based dosing provides more accurate medication calculations than weight-based dosing, especially for chemotherapy and high-risk medications.
Cardiac Assessments
Cardiac output and stroke volume are often indexed to BSA to normalize values across different body sizes for accurate comparison.
Burn Assessment
BSA is crucial for calculating burn percentage using the Rule of Nines and determining fluid resuscitation requirements in burn patients.
Laboratory Values
Many laboratory reference ranges and physiological parameters are normalized to BSA for more accurate clinical interpretation.
Related Calculators
Understanding Body Surface Area
Medical applications and clinical significance of BSA calculations
Body Surface Area (BSA) is a critical measurement in clinical medicine, representing the total surface area of the human body. BSA calculations are essential for accurate drug dosing, particularly in chemotherapy protocols, cardiac output assessments, and burn injury evaluations. Our BSA calculator uses established medical formulas including Du Bois, Mosteller, Boyd, and Haycock equations, following guidelines from organizations like the National Comprehensive Cancer Network and the American College of Cardiology. Healthcare professionals rely on BSA for precise medical calculations that ensure patient safety and treatment efficacy. Complement your medical assessments with our BMI calculator for comprehensive health evaluation.
Drug Dosing
BSA provides more accurate medication dosing than weight alone, especially for chemotherapy and high-risk drugs.
Cardiac Assessment
Cardiac output and stroke volume are indexed to BSA for accurate cardiovascular evaluations.
Burn Evaluation
Essential for calculating burn percentage and determining fluid resuscitation requirements.
BSA Formula Comparison
Different BSA formulas have been developed over time, each with specific advantages and clinical applications. The choice of formula often depends on the clinical setting, patient population, and institutional preferences. Understanding the differences helps healthcare professionals select the most appropriate formula for their specific needs.
Mosteller Formula
📊 Most widely recommended:
BSA = √[(Height × Weight) / 3600]
✅ Advantages:
Simple calculation, widely accepted, good accuracy across age groups
Du Bois Formula
The original BSA formula developed in 1916, still used in some clinical settings.
BSA = 0.007184 × W^0.425 × H^0.725
Boyd Formula
Alternative formula that considers body weight distribution more precisely.
Complex logarithmic calculation
Medical Applications of BSA
BSA calculations are fundamental to numerous medical applications, providing standardized measurements that improve patient care and treatment outcomes:
Chemotherapy Dosing
Most chemotherapy protocols specify drug doses in milligrams per square meter of BSA (mg/m²). This approach:
- Reduces toxicity risk: BSA-based dosing helps prevent overdosing in smaller patients and underdosing in larger patients
- Improves efficacy: Standardized dosing across different body sizes ensures consistent drug exposure
- Enables protocol standardization: Clinical trials and treatment protocols can be applied universally
- Facilitates dose modifications: Adjustments for toxicity or response can be made systematically
Cardiac Output Calculations
Cardiac index (CI) is calculated by dividing cardiac output by BSA, providing normalized cardiovascular assessments:
Normal Cardiac Index: 2.5-4.0 L/min/m²
This normalization allows comparison of cardiac function across patients of different sizes
Burn Assessment and Treatment
BSA is crucial for burn injury evaluation using the Rule of Nines and fluid resuscitation calculations:
🔥 Burn Percentage Calculation
Total body surface area burned determines treatment protocols and prognosis
💧 Fluid Resuscitation
Parkland formula uses BSA and burn percentage to calculate fluid requirements
Clinical Reference Ranges
Understanding normal BSA ranges helps healthcare professionals interpret calculated values:
Adult Ranges
- Average adult: 1.6-1.9 m²
- Standard reference: 1.73 m²
- Range: 1.33-2.2 m²
- Gender variations exist
Pediatric Ranges
- Newborn: 0.25 m²
- 1 year: 0.5 m²
- 5 years: 0.8 m²
- 10 years: 1.14 m²
Special Populations
- Obese patients: Formula adjustments
- Elderly: Age-related considerations
- Athletes: Muscle mass impact
- Amputees: Modified calculations
BSA in Drug Development
Pharmaceutical research and clinical trials extensively use BSA for standardizing drug dosing across diverse populations:
- Phase I trials: Initial dose escalation studies use BSA to determine maximum tolerated doses
- Regulatory submissions: FDA and EMA guidelines often require BSA-based dosing rationale
- Pediatric dosing: Extrapolation from adult doses frequently uses BSA scaling
- Oncology protocols: Nearly all cancer drug trials specify doses per square meter of BSA
Limitations and Considerations
While BSA is widely used, healthcare professionals should be aware of its limitations:
Formula Variations
Different formulas can yield varying results, with differences up to 10% in some cases.
Body Composition
BSA doesn’t account for muscle mass, fat distribution, or body composition variations.
Extreme Body Sizes
Very obese or very thin patients may require alternative dosing strategies.
Despite these limitations, BSA remains the gold standard for many clinical applications. Healthcare professionals should use clinical judgment when applying BSA calculations and consider patient-specific factors. Explore our health & fitness calculator category for additional medical tools, including ideal body weight calculator and body fat calculator for comprehensive patient assessment.
Frequently Asked Questions
Get expert answers to common BSA calculation questions
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