Average adult BSA is about 1.7 m² for women and 1.9 m² for men. Children have lower BSA proportional to their size. BSA typically ranges from 1.5-2.2 m² in adults.

Why is BSA used for drug dosing?

BSA correlates better with blood volume, cardiac output, and organ size than weight alone. This provides more accurate dosing, especially for drugs with narrow safety margins like chemotherapy.

How is BSA used for burns?

The 'Rule of Nines' divides body surface into percentages. BSA helps calculate fluid resuscitation needs—burns over 20% BSA require aggressive IV fluids using formulas like Parkland.

Health

Body Surface Area Calculator

Free BSA calculator to compute body surface area in m² using Mosteller, Du Bois, Haycock, and Gehan-George medical formulas.

Unit System

Formula

Weight

Height

Mosteller (1987)

Simplified formula, widely accepted

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Calculate Your Body Surface Area (BSA)

Body Surface Area is used in medicine to calculate drug dosages, determine burn severity, and assess body size. Our calculator supports multiple formulas including Mosteller (most common), Du Bois, Haycock, and more.

Understanding Body Surface Area

BSA measures total skin surface area in square meters. Unlike BMI, BSA accounts for both height and weight to estimate actual body size. Average adult BSA is 1.7-2.0 m². BSA is preferred over weight for dosing many medications because it better correlates with metabolic rate.

Mosteller Formula (Most Common)

BSA = √((Height × Weight) / 3600)

How to Use the Calculator

Common Use Cases

Medical Dosing

Calculate appropriate medication doses.

Burn Assessment

Determine percentage of body affected.

Health Metrics

Complement BMI with BSA measurement.

Frequently Asked Questions

Mosteller is most widely used due to simplicity. Du Bois is the classic formula. Haycock is preferred for children. Your healthcare provider may specify which to use.