DuBois Body Surface Area Calculator
Enter your height and weight to estimate body surface area (BSA) using the classic DuBois & DuBois equation.
Formula used: BSA = 0.007184 × Height(cm)0.725 × Weight(kg)0.425
What is Body Surface Area (BSA)?
Body surface area is an estimate of the total external area of the human body, expressed in square meters (m²). In healthcare, BSA is often used for clinical decisions where body size matters more than body weight alone. The DuBois formula is one of the oldest and most widely recognized methods for estimating BSA.
The DuBois Formula Explained
DuBois & DuBois (1916):
BSA (m²) = 0.007184 × Height(cm)0.725 × Weight(kg)0.425
This equation combines height and weight with non-linear exponents, which helps produce a smoother estimate of surface area across different body sizes. Despite being developed over a century ago, it remains a standard reference in many medical calculators and educational materials.
How to Use This Calculator
- Enter height in centimeters (cm).
- Enter weight in kilograms (kg).
- Click Calculate BSA.
- Read the estimated BSA in square meters and square feet.
Tip: If you know imperial measurements, convert first: inches × 2.54 = cm, and pounds × 0.453592 = kg.
Why BSA Matters in Clinical Practice
1) Medication Dosing
Several drugs, especially in oncology, are prescribed per square meter of body surface area. This helps tailor dosing to body size more precisely than fixed dosing.
2) Physiological Estimation
BSA is sometimes used in calculations for cardiac index and renal metrics. These values may be normalized to BSA to compare patients of different body sizes.
3) Burn Assessment
In burn care, surface area concepts are central. While burn charts use specific anatomical percentages, BSA remains an important overall body-size metric.
Typical Adult BSA Values
| Example Profile | Approximate BSA (m²) |
|---|---|
| Small-framed adult | 1.5 – 1.7 |
| Average adult | 1.7 – 2.0 |
| Larger adult | 2.0 – 2.3+ |
Limitations of the DuBois Method
Like all formulas, DuBois provides an estimate, not a direct measurement. It may be less precise in children, very muscular individuals, and people at weight extremes. Clinical teams may choose different formulas depending on patient population and local protocol.
- Mosteller: Simple and popular for bedside use.
- Haycock: Often discussed for pediatric contexts.
- Gehan and George: Another alternative in research and clinical software.
Quick FAQ
Is BSA the same as BMI?
No. BMI (body mass index) estimates weight status relative to height. BSA estimates skin surface area and is used differently, especially in dosing and normalization calculations.
Can I use this calculator for children?
You can compute a numeric estimate, but pediatric clinical decisions should always follow professional guidance and age-appropriate standards.
Is a higher BSA better?
Not necessarily. BSA is a size metric, not a direct marker of health, fitness, or disease risk.
Final Note
This DuBois body surface area calculator is intended for educational and informational use. It can be helpful for quick estimates, but it does not replace medical judgment. If a result will influence treatment or medication, consult a licensed healthcare professional.