Body Surface Area Calculator

Modify the values and click the Calculate button to use

BSA: 1.85 m²

Results are shown for four common body-surface-area formulas. Differences are usually small; use the method your clinician or protocol specifies.

BSA formulas

Formula	m²	ft²	in²
Du Bois	1.85	19.95	2873
Mosteller	1.85	19.91	2868
Haycock	1.85	19.94	2871
Gehan & George	1.86	20.01	2882

What this body surface area calculator does

Body surface area (BSA) is an estimate of the total surface area of the body. It is used in some clinical settings, including certain drug dosing and physiologic calculations. This calculator shows four common formulas: Du Bois, Mosteller, Haycock, and Gehan & George.

The formulas usually agree within a few percent for adults. The choice of formula may depend on the clinical protocol.

How to use this calculator

Choose US or metric units.
Enter height and weight.
Click Calculate to see BSA in square meters, square feet, and square inches.

The default example is 155 lb and 5 ft 9 in.

BSA formulas

Du Bois:          0.007184 × W^0.425 × H^0.725
Mosteller:        sqrt(W × H / 3600)
Haycock:          0.024265 × W^0.5378 × H^0.3964
Gehan & George:   0.0235 × W^0.51456 × H^0.42246

W is weight in kilograms and H is height in centimeters.

What the results mean

The default example gives about 1.85 m² by the first three formulas and 1.86 m² by Gehan & George. Small differences are normal.

BSA is not a measure of fitness or body composition. It does not replace a clinical assessment or a dosing protocol.

Assumptions and limitations

The formulas were developed in specific populations and may be less accurate in infants, very obese people, or people with unusual body proportions. They do not account for amputation, edema, or muscle mass.

Do not use BSA for medication dosing without the protocol and supervision of a qualified clinician. This page is for education and estimation.

Frequently asked questions

Which BSA formula is best?

There is no universal best formula. Mosteller is simple and common; Du Bois is widely recognized. Follow the protocol used by your clinician or institution.

Why are there different units?

BSA is usually reported in square meters, but square feet and square inches are provided for convenience.

Can I use this for children?

Pediatric BSA uses the same formulas but the clinical interpretation and dosing differ. Use a pediatric protocol and specialist guidance.

Does BSA measure body fat?

No. BSA is a surface-area estimate, not a body-composition measure.

Reference tables

BSA formulas

Formula	Results in different units
Du Bois	0.007184 × weight(kg)^0.425 × height(cm)^0.725
Mosteller	√(height(cm) × weight(kg) ÷ 3,600)
Haycock	0.024265 × weight(kg)^0.5378 × height(cm)^0.3964
Boyd	0.0003207 × height(cm)^0.3 × weight(kg)^(0.7285 − 0.0188 × log10(weight))

Formula selection

Gender	male female
Male	Formulas are not sex-specific; use the same equation
Female	Formulas are not sex-specific; use the same equation

BSA estimates vary by formula. Use the method specified by your clinical protocol.

Source

References:

Disclaimer

This calculator is for informational and educational purposes only. It is not medical advice or a dosing instruction. Confirm clinical use with a qualified clinician.

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