Updated Health & Body Size

Body Surface Area (BSA) Calculator

Calculate body surface area using multiple medical formulas, estimate BMI, plan drug dosage by BSA, and convert height, weight, and area units.

BSA (Mosteller) Multi-Formula BSA BSA + BMI BSA Dosage & Units

All-in-One Body Surface Area (BSA) Calculator

Switch between BSA formulas, BMI, BSA-based dosage, and unit conversion. Supports cm/in and kg/lb for global use.

Mosteller BSA: BSA = √((height(cm) × weight(kg)) ÷ 3600). Widely used in clinical settings.

Different BSA formulas are used in research, pediatrics, and oncology. This tab lets you compare them quickly.

This tab gives a quick view of both body surface area and body mass index from the same height and weight.

This tool is for educational planning only and does not replace medical judgment. Always confirm dosages with a qualified clinician.

Weight Converter (kg ↔ lb)

Height Converter (cm ↔ in)

Area Converter (m² ↔ ft²)

Use these converters to match medical records, local guidelines, or research values that use different units.

Body Surface Area (BSA) Calculator – Multi-Formula, BMI & Dosage

This Body Surface Area (BSA) Calculator helps you estimate a person’s external body area in square meters (m²). BSA is widely used in medicine to dose certain medications, interpret lab values, and standardize physiological measurements.

Mosteller BSA Formula

One of the most popular and simple BSA formulas is the Mosteller formula:

BSA (m²) = √((Height(cm) × Weight(kg)) ÷ 3600)

It balances ease of calculation with reasonable accuracy across a wide range of body sizes.

Other Common BSA Formulas

The multi-formula tab lets you compare several widely cited methods:

  • Du Bois: BSA = 0.007184 × Height(cm)0.725 × Weight(kg)0.425
  • Haycock: BSA = 0.024265 × Height(cm)0.3964 × Weight(kg)0.5378
  • Gehan–George: BSA = 0.0235 × Height(cm)0.42246 × Weight(kg)0.51456
  • Boyd: A more complex formula that adjusts for weight using a logarithmic term.

BSA, BMI, and Ideal Weight Range

While BSA focuses on total body surface, BMI (Body Mass Index) focuses on weight relative to height:

BMI = Weight(kg) ÷ Height(m)2

In the BSA + BMI tab, the calculator displays both BSA and BMI and estimates an “ideal” weight range corresponding to a BMI of about 18.5–24.9 for the given height.

BSA-Based Drug Dosage

For some medications, especially in oncology and pediatrics, doses are prescribed in mg/m². The dosage tab multiplies your BSA by the chosen mg/m² dose and optionally shows how this compares to mg/kg if you also enter weight.

The outputs are for informational and educational use only and must not replace professional medical advice, clinical judgment, or local dosing protocols.

Units and Conversions

Because height and weight can be recorded in different units (cm vs inches, kg vs pounds) and body surface area may be shown in m² or ft², the unit converter tab helps you switch between these systems quickly.

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