Body Surface Area (BSA) Calculator

What Is the Body Surface Area (BSA) Calculator?

The Body Surface Area (BSA) Calculator allows you to calculate the total surface area of the human body. BSA is an important metric used in various clinical purposes, such as calculating doses of chemotherapy and determining the cardiac index.

We provide calculations based on the most widely recognized formulas, including Du Bois, Mosteller, Haycock, Gehan and George, Boyd, Fujimoto, Takahira, and Schlich.

BSA vs BMI vs Lean Body Mass

These three metrics are often searched together, but they measure different things. BSA (Body Surface Area) estimates the total surface area of the body from height and weight, and is used mainly for medical dosing — chemotherapy, cardiac index, and burn-treatment calculations — because drug distribution and metabolic rate correlate more closely with body surface than with weight alone. BMI Calculator (Body Mass Index) is a simple ratio of weight to height squared, used as a general screening tool for weight categories, but it doesn't distinguish between muscle and fat mass. Lean Body Mass Calculator estimates the weight of everything in the body except fat — muscle, bone, organs, water — and is used mainly in fitness and nutrition contexts. A clinician calculating a chemotherapy dose will use BSA; a doctor screening for obesity risk will use BMI; a trainer estimating calorie needs will often use Lean Body Mass. None of the three replaces the others, since each is built for a different purpose.

Practical Examples & Reference Guide

Example Output for a Standard Adult

For an average adult male with a height of 180 cm (5' 11") and a weight of 75 kg (165 lbs), the results from different formulas are:

Formula	BSA (m²)	BSA (ft²)
Du Bois	1.94	20.84
Mosteller	1.94	20.85
Haycock	1.95	21.03
Gehan & George	1.95	21.04
Boyd	1.97	21.21
Fujimoto	1.90	20.50
Takahira	1.95	20.97
Schlich (Male)	1.96	21.14

Note: Results may slightly vary based on the specific formula used. After calculating your BSA, you may also want to use the Ideal Weight Calculator or BMR Calculator as a natural next step to get a more complete picture of your health.

Why BSA Matters in Medicine

Body Surface Area (BSA) is a better indicator of metabolic mass than body weight because it is less affected by abnormal adipose mass. It is commonly used in medicine to determine:

• Safe chemotherapy dosages.
• Glucocorticoid dosages.
• Renal function assessments (e.g., estimating GFR).
• Cardiac index.

BSA Formulas Explained (with equations)

Each BSA formula uses height and weight, but the constants and exponents differ slightly based on the population data each was built from:

• Du Bois & Du Bois (1916): BSA = 0.007184 × Height(cm)^0.725 × Weight(kg)^0.425 — the original and still one of the most widely cited formulas in clinical literature, though it was derived from a small sample of only nine subjects.
• Mosteller (1987): BSA = √([Height(cm) × Weight(kg)] / 3600) — the simplest to calculate by hand, which is why it's the version most commonly taught in nursing and pharmacy programs today.
• Haycock (1978): BSA = 0.024265 × Height(cm)^0.3964 × Weight(kg)^0.5378 — developed specifically using data from infants and children, and generally preferred for pediatric dosing.
• Gehan and George (1970): BSA = 0.0235 × Height(cm)^0.42246 × Weight(kg)^0.51456 — refined the Du Bois approach with a much larger sample size.
• Boyd (1935): BSA = 0.0003207 × Height(cm)^0.3 × Weight(g)^(0.7285 − 0.0188 × log10(Weight in g)) — the most mathematically complex of the group, with a weight-dependent exponent.
• Fujimoto (1968): BSA = 0.008883 × Height(cm)^0.663 × Weight(kg)^0.444 — developed using Japanese population data, and sometimes preferred in East Asian clinical settings.
• Takahira: BSA = 0.007241 × Height(cm)^0.725 × Weight(kg)^0.425 — closely related to the Du Bois formula, also based on Japanese population studies.
• Schlich (2010): Uses separate equations for men and women, reflecting differences in average body proportions between sexes — one of the more recent additions to clinical use.

Normal BSA Ranges by Age and Gender

Group	Average BSA (m²)	Average BSA (ft²)
Newborn	0.25	2.69
Two-year-old child	0.50	5.38
Ten-year-old child	1.14	12.27
Adult female	1.60	17.22
Adult male	1.90	20.45