Body Surface Area Calculator

Calculate your body surface area (BSA) using the Du Bois formula, based on your weight and height.

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Enter your weight and height to calculate your body surface area (BSA) using the Du Bois formula.
kg
cm

Your result

1.81 m²

Body surface area

AI explanation

Formula

BSA(m²) = 0.007184 × weight(kg)^0.425 × height(cm)^0.725

Worked example

70kg, 170cm

Worked example: 70kg, 170cm
FieldValue
Weight70
Height170
Body surface area1.81

Assumptions

  • Uses the Du Bois & Du Bois formula (1916), still the most widely used BSA estimate in clinical dosing contexts, despite being derived from a small original sample.
  • Informational only — clinical medication dosing based on BSA should always be confirmed by a qualified healthcare professional.

Frequently asked questions

What is body surface area used for?

BSA is commonly used in medicine to calculate medication dosages (especially chemotherapy) and to normalize physiological measurements like cardiac output between people of different sizes.

Why does the Du Bois formula use unusual exponents like 0.425 and 0.725?

These exponents were empirically fitted from body-surface measurements on a small group of subjects in 1916 and have remained in wide clinical use since, despite newer formulas being proposed.

What's a typical BSA for an adult?

Most adults have a BSA between about 1.6 and 2.0 m², though it varies with both height and weight.

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Related articles

Health & Fitness1 min read

How Body Surface Area Is Calculated From Weight and Height

Body surface area comes from the century-old Du Bois formula — weight and height each raised to their own fractional power and multiplied together — still the standard estimate behind clinical medication dosing today.

Read guide
Health & Fitness2 min read

Why the Same eGFR Can Mean a Different Absolute Kidney Function for Different People

An eGFR of 91.7 is reported per a standardized 1.73m² body surface area — de-normalizing it with a real, much smaller or larger body surface area reveals two very different absolute filtration rates hiding behind the identical eGFR number.

Read guide

Sources

This calculator provides a general estimate only and does not constitute personalized medical advice. Medication dosing based on BSA must be confirmed by a qualified healthcare professional.

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