Body Surface Area (Du Bois)

Estimate body surface area (BSA) with the classical Du Bois & Du Bois equation—ideal for preparing medication doses, infusion rates, or metabolic calculations.

Use current body mass in kilograms as recorded on a calibrated scale.
Measure standing height without shoes using a stadiometer for best accuracy.

Informational tool only. Always corroborate BSA with institutional protocols and a licensed clinician before prescribing or adjusting therapy.

Examples

  • 72.5 kg adult at 178 cm ⇒ 1.92 m², often used for chemotherapy dosing
  • 54 kg patient at 160 cm ⇒ 1.55 m², helpful when titrating IV fluids
  • 98 kg athlete at 188 cm ⇒ 2.24 m², useful for indexing cardiac output

FAQ

Why is the Du Bois equation still referenced?

Despite originating in 1916, it remains a clinical baseline because it aligns closely with average adult body shapes and is easy to compute.

Should I convert imperial measurements manually?

Yes. Convert pounds to kilograms and inches to centimeters before entering values to maintain accuracy.

How should I interpret the result?

Use the square-metre value to scale lab results (e.g., eGFR in mL/min/1.73 m²) or to adjust medication doses published per square metre.

Does body composition change the estimate?

Extremes in obesity or cachexia can introduce bias. Cross-check with clinician judgement or imaging-derived surface measurements in critical care.

Additional Information

  • Applies the Du Bois coefficient 0.007184 × weight^0.425 × height^0.725 with metric inputs only.
  • BSA standardizes physiologic metrics like glomerular filtration rate (GFR), cardiac index, and medication doses.
  • For pediatric assessments consider comparing with alternative formulas (Haycock, Mosteller) to evaluate sensitivity.