Body Surface Area Calculator (BSA)
This body surface area calculator gives you your BSA in square meters using the two most widely used clinical formulas: Mosteller and Du Bois. Just enter your weight in kilograms and your height in centimeters and both results appear instantly, so you can compare them side by side. Body surface area (BSA) is often a better reference than body weight alone for scaling physiological quantities, because it correlates well with metabolic rate, blood volume and organ function. Clinicians rely on it to individualize chemotherapy and other drug doses, to index cardiac output and kidney function, and to compare patients of very different builds on a fair, size-adjusted basis.
Body surface area (Mosteller)
Body surface area (Du Bois)
Body surface area is used to estimate medication doses and clinical parameters (cardiac index, glomerular filtration rate, etc.). This result is an informational estimate and is not medical advice: dosing decisions should be made by a healthcare professional.
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How it works
The calculator applies two classic equations. The Mosteller formula is BSA (m²) = √(weight × height / 3600), where weight is in kilograms and height in centimeters — a simple square root that is easy to reproduce and now the most common choice in practice. The Du Bois formula, published in 1916, is BSA (m²) = 0.007184 × weight^0.425 × height^0.725. Both return an area in square meters and normally agree to within a few percent; small differences come from the different data sets used to fit each equation. A typical adult falls near 1.6–2.0 m². In oncology and cardiology, BSA is used to calculate dosing (mg per m²) and to compute indexed values such as the cardiac index, so a reliable estimate matters.
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Preguntas frecuentes
- What is body surface area (BSA)?
- Body surface area is the total external surface of the body, expressed in square meters. It is estimated from weight and height using validated formulas. Because it tracks metabolic rate and organ size better than weight alone, it is widely used in medicine to scale drug doses and physiological measurements.
- Which formula should I use, Mosteller or Du Bois?
- Both are accepted and usually agree to within a few percent. The Mosteller formula is a simple square root and is now the most common in daily practice, while the Du Bois formula from 1916 is a long-standing standard. This calculator shows both so you can compare; follow your institution's preferred method if one is specified.
- What is a normal BSA value?
- For most adults, BSA falls roughly between 1.6 and 2.0 m². Around 1.7 m² is often quoted as an average value. Larger, taller people have a higher BSA and smaller people a lower one; there is no single "correct" number, since it simply reflects body size.
- Why is BSA used to calculate medication doses?
- Many drugs, especially in chemotherapy, are dosed per square meter (mg/m²) because BSA correlates with blood volume, kidney and liver function, and metabolism better than weight alone. Dosing by BSA aims to give a more consistent drug exposure across patients of different sizes.
- Is this calculator a substitute for medical advice?
- No. It is an informational tool that estimates BSA from your weight and height. Actual dosing and clinical decisions depend on many factors and must be made by a qualified healthcare professional, who may also account for rounded, capped or adjusted BSA values.