Body Surface Area Calculator (BSA) - Mosteller & Du Bois

Your Measurements

Height (cm)

Weight (kg)

Your Results

Mosteller Formula

0.00 m²

Most commonly used

Du Bois Formula

0.00 m²

Classic reference method

Reference Ranges

Average Adult Male: 1.9 m²

Average Adult Female: 1.6 m²

Typical Adult Range: 1.5 - 2.2 m²

Newborn (3.5 kg): ~0.25 m²

💡 Clinical Applications

Medication Dosing: Chemotherapy and other medications are often dosed per m² BSA
Cardiac Index: Cardiac output normalized by BSA (normal: 2.5-4.0 L/min/m²)
Glomerular Filtration Rate (GFR): Kidney function indexed to BSA
Burn Assessment: Rule of Nines uses BSA percentages for fluid resuscitation
Metabolism Studies: Basal metabolic rate often expressed per m² BSA

How It Works

Mosteller Formula (1987)

BSA (m²) = √[(Height(cm) × Weight(kg)) / 3600]

The Mosteller formula is the most commonly used due to its simplicity and accuracy. It's easier to calculate without a calculator compared to Du Bois.

Du Bois & Du Bois Formula (1916)

BSA (m²) = 0.007184 × Height(cm)^0.725 × Weight(kg)^0.425

The Du Bois formula is the classic reference method, derived from measurements of 9 subjects in 1916. It remains widely validated and used in research.

Step-by-Step Calculation

Example: Height = 175 cm, Weight = 75 kg

Mosteller Method:
Step 1: Multiply height by weight: 175 × 75 = 13,125
Step 2: Divide by 3600: 13,125 / 3600 = 3.646
Step 3: Take square root: √3.646 = 1.91 m²

Du Bois Method:
BSA = 0.007184 × 175^0.725 × 75^0.425
BSA = 0.007184 × 48.86 × 6.03
BSA = 1.92 m²

Frequently Asked Questions

What is body surface area used for? ▼

BSA is crucial in medicine for calculating drug dosages (especially chemotherapy), determining cardiac index, assessing burn severity, normalizing kidney function (GFR), and estimating metabolic rate. It provides a more accurate basis for dosing than weight alone.

Which formula is more accurate? ▼

Both Mosteller and Du Bois formulas are highly accurate and correlate well (typically within 1-2%). Mosteller is preferred for its simplicity, while Du Bois is the classic reference. The difference is clinically insignificant for most applications.

Why not just use body weight for dosing? ▼

BSA better reflects metabolic mass and physiological function than weight alone. Two people with the same weight but different heights have different metabolic needs. BSA accounts for both dimensions, providing more accurate dosing, especially for potent medications.

What's a normal BSA range? ▼

Average adult males have BSA around 1.9 m², females around 1.6 m². Typical adult range is 1.5-2.2 m². Children have lower BSA (newborn ~0.25 m²). BSA varies with height and weight, not just body composition.

Can BSA be used for fitness purposes? ▼

BSA is primarily a clinical tool. For fitness, metrics like lean body mass, body fat percentage, or BMI are more relevant. However, BSA is useful for normalizing VO2 max and other physiological measurements in exercise science.