formula.expert

Body Surface Area (Du Bois Formula)

Also known as Du Bois body surface area

BSA=0.007184⋅hcm0.725⋅mkg0.425\mathrm{BSA} = 0.007184 \cdot h_{cm}^{0.725} \cdot m_{kg}^{0.425}

Worked example: 1.80 m, 75 kg → 1.94239 m2 — press Try an example to run it live, then adjust anything.

Enter your known values, leave one input blank, and solves for the missing one. Tap a variable’s symbol to see what it means, with a typical value. Try different units for next level excitement!

Learning zone

Body Surface Area (Du Bois Formula) explained

hmBSA

Delafield Du Bois and Eugene Du Bois built this fit in 1916 by coating nine people in molten paraffin, cutting the shells into pieces, and measuring the flattened area. Nine subjects, one of them a child and one a person with severe wasting, produced the exponents 0.725 on height and 0.425 on mass that oncology and cardiology still use a century later.

The exponents encode something real: area grows more slowly than volume, so a body twice as heavy has nowhere near twice the skin. That is also why the formula drifts at the extremes of its sample, over-predicting for very obese bodies where mass rises far faster than surface. Newer fits by Haycock, Gehan and Mosteller correct for that to varying degrees, and a hospital will specify which one its protocols expect. Comparing this page's answer with the Mosteller page is a good way to see how much of a "body surface area" is genuinely known and how much is convention.

Body Surface Area (Du Bois Formula)

BSA=0.007184⋅hcm0.725⋅mkg0.425\mathrm{BSA} = 0.007184 \cdot h_{cm}^{0.725} \cdot m_{kg}^{0.425}
Where
  • BSA\mathrm{BSA}= Body surface area (m²)
  • hh= Height (m)
  • mm= Body mass (kg)

Missing one of these? Work it out first, then come back

Part of this formula set

Body and fitness numbers

6 formulasBMI, maximum and target heart rate, body surface area and calories burned — with what each number cannot tell you.