UnitConv

Body Surface Area (BSA) Calculator

Estimate your body surface area with five formulas

Your Body Surface Area
1.82
m²
Representative value (Mosteller)
Mosteller
1.818
m²
Du Bois
1.810
m²
Haycock
1.826
m²
Gehan & George
1.831
m²
Boyd
1.835
m²

Average of all formulas: 1.824 m²

Compare Formulas

Mosteller1.818 m²
Du Bois1.810 m²
Haycock1.826 m²
Gehan & George1.831 m²
Boyd1.835 m²

Formulas Used

Du Bois: BSA = 0.007184 x kg^0.425 x cm^0.725

Mosteller: BSA = sqrt( (cm x kg) / 3600 )

Haycock: BSA = 0.024265 x kg^0.5378 x cm^0.3964

Gehan & George: BSA = 0.0235 x kg^0.51456 x cm^0.42246

Boyd: BSA = 0.0003207 x cm^0.3 x g^(0.7285 - 0.0188 x log10(g))

All formulas estimate body surface area in square meters from height and weight. Mosteller is the simplest and most widely used clinically; Du Bois is the classic reference.

What is a BSA Calculator?

A Body Surface Area (BSA) calculator estimates the total surface area of the human body in square meters from your height and weight. BSA is used widely in medicine - to size chemotherapy and other drug doses, to index cardiac output and kidney function, and to assess burns - because it scales physiological measures better than body weight alone. This tool reports five established formulas so you can compare them: Mosteller (the simplest and most common clinically), Du Bois & Du Bois (the historic reference), Haycock, Gehan & George, and Boyd. Both metric (cm/kg) and imperial (ft-in/lb) units are supported.

How to Use

1. Choose metric (cm/kg) or imperial (ft-in/lb) units. 2. Enter your height and weight. 3. Read your BSA - the large number is the Mosteller result (the representative value), with the other four formulas shown alongside. 4. Use the comparison bars to see how the formulas differ.

Formula & Definition

Mosteller (representative): BSA = sqrt( (height(cm) x weight(kg)) / 3600 ) Du Bois & Du Bois (classic): BSA = 0.007184 x weight(kg)^0.425 x height(cm)^0.725 Haycock: BSA = 0.024265 x kg^0.5378 x cm^0.3964 Gehan & George: BSA = 0.0235 x kg^0.51456 x cm^0.42246 Boyd: BSA = 0.0003207 x cm^0.3 x grams^(0.7285 - 0.0188 x log10(grams)). For example, a person 170 cm tall weighing 70 kg has a Mosteller BSA of about 1.82 m² and a Du Bois BSA of about 1.81 m².

Interpreting Results

An average adult has a BSA of roughly 1.7 m² (about 1.9 m² for men and 1.6 m² for women). The five formulas typically agree to within a few percent, so any of them is suitable for everyday reference. Mosteller is favored in clinical practice for its simplicity, while Du Bois is the long-standing standard. BSA is most often used to standardize drug dosing and physiological indices rather than as a personal health metric on its own.

Frequently Asked Questions

What is body surface area (BSA)? ▾

BSA is the total external surface area of the body, expressed in square meters. It is calculated from height and weight and is widely used in medicine to scale doses and physiological measures.

Which BSA formula should I use? ▾

Mosteller is the most popular in clinical practice because it is simple and accurate; Du Bois & Du Bois is the classic reference. The five formulas usually differ by only a few percent.

What is a normal BSA? ▾

An average adult is around 1.7 m² - roughly 1.9 m² for men and 1.6 m² for women. Values depend mainly on body size.

Why is BSA used for drug dosing? ▾

Many physiological processes, such as metabolism and blood volume, scale more closely with surface area than with body weight, so dosing by BSA can be more consistent across body sizes - notably in chemotherapy.

Is BSA the same as BMI? ▾

No. BMI relates weight to height to gauge whether weight is healthy, while BSA estimates total body surface area for dosing and physiological scaling.

This tool provides a general estimate, not individual medical advice. BSA formulas are approximations and clinical decisions should be made by a qualified healthcare professional.