Updated · Methodology: named formula library
Body Surface Area Calculator
Du Bois BSA from height and weight.
Mosteller formula: √(175.0 cm × 70.0 kg / 3600) = 1.84 m².
Why This Calculation Matters
The Body Surface Area Calculator turns a well-known health formula into an instant lookup. It's most useful when you're tracking a number over time or comparing yourself against published reference ranges from bodies like the CDC, NIH, or WHO. Use it as one data point among many, not a diagnosis.
How to Use This Calculator
- Enter your values in the input fields, each one has a label and help text explaining what to type.
- Results appear instantly as you type; there's no "calculate" button to press.
- Change any input to compare scenarios side by side.
All math happens in your browser. Nothing you type is sent to a server, saved, or shared.
Reading Your Result
A single number tells you less than a trend. Track this value over weeks or months rather than obsessing over day-to-day variation. Hydration, sleep, and timing can all shift short-term readings without reflecting any real change.
How to Use
Enter values in the fields on the left. Results update as you type, no submit button needed.
Understanding Results
Each output shows the calculated figure plus a breakdown of contributing inputs. Compare scenarios by editing any value.
Accuracy Notes
Every Body Surface Area Calculator on CalcIntel uses a documented formula. Results are estimates, real outcomes depend on assumptions and market conditions not captured in a simplified calculation.
Formula
Metric: BMI = kg / m². Imperial: BMI = (lb / in²) × 703. WHO categories: underweight <18.5, normal 18.5-24.9, overweight 25-29.9, obese ≥30.
Worked Example
175 cm, 70 kg adult
- height
- 175
- weight
- 70
- Result
- 1.84 m²
√((175 × 70) / 3600) = 1.84 m² (Mosteller formula).
When to Use This Calculator
- Track personal health metrics over time alongside guidance from your clinician.
- Understand how lifestyle changes may influence a given health number.
- Compare values against recognized reference ranges from CDC, NIH, or WHO.
Limitations & Common Mistakes
- Not a substitute for medical advice. Always consult a qualified clinician for anything that affects your care.
- Population-level formulas don't account for individual medical history, medications, or body composition nuances.
- Reference ranges evolve, use current CDC/NIH/WHO values when accuracy matters.
Frequently Asked Questions
Why use the Mosteller formula for BSA?
Mosteller's formula — BSA(m²) = √((height × weight) / 3600) — is the most widely-used BSA calculation in clinical oncology, pediatrics, and intensive care. It's accurate to within 3–5% of measured BSA for most body types.
What's a normal BSA?
Adult average: 1.7 m² (women) to 1.9 m² (men). Pediatric: scales roughly with age and weight; a 1-year-old is ~0.5 m², a 10-year-old ~1.1 m². Used to dose chemotherapy, fluids, and cardiac index.
Mosteller vs Du Bois vs Boyd?
All three give very similar results (within 5%) for adults. Mosteller is preferred for pediatric oncology dosing; Du Bois is the historical reference; Boyd is sometimes used for very obese patients. Mosteller is simplest and clinically standard.
How is BSA used clinically?
Chemotherapy dosing (mg/m²), fluid resuscitation in burns, cardiac index (cardiac output / BSA), and pediatric drug dosing. BSA-based dosing is more accurate than weight-based for many drugs because it correlates better with metabolic rate.
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Related guides
- TDEE: The Only Calorie Number That Actually Drives Weight ChangeBMR tells you the baseline. Calorie intake tells you the input. TDEE is the number that decides whether you lose, maintain, or gain, and it is the one most people miscalculate.
- BMI vs. Body Fat Percentage: Which Number Actually Measures HealthBMI is free and fast. Body fat percentage is more accurate. Waist-to-hip ratio predicts cardiovascular risk better than either. Here is when to use which, and what the CDC and WHO actually recommend.
Source: BLS Consumer Price Index, 2026.