Body surface area (BSA) estimates the total area of your skin in m² from height and weight. The simple Mosteller formula — √(height_cm × weight_kg / 3600) — is the most used; the classic Du Bois formula usually agrees within a couple of percent. BSA scales many drug doses and indexes physiological measures better than weight alone.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: the Mosteller and Du Bois formulas, recomputed in code. Educational estimate, not medical advice.
The formulas
Mosteller multiplies height and weight, divides by 3600, and takes the square root — easy to do mentally. Du Bois raises height and weight to fixed powers; it dates from 1916 and remains a reference. Inches are converted to centimetres (× 2.54) and pounds to kilograms (× 0.453592) before either formula is applied.
Worked example — 170 cm, 70 kg
Both formulas put this person at about 1.8 m², just above the average adult of ~1.7 m². For 180 cm / 80 kg the BSA is about 2.0 m², and for 160 cm / 55 kg about 1.56 m² — the two methods agreeing closely each time.
Frequently Asked Questions
BSA = √(height_cm × weight_kg / 3600). 170 cm, 70 kg ≈ 1.82 m². The most used BSA formula.
Scaling drug doses (chemo especially), indexing cardiac output and GFR, estimating metabolic rate.
0.007184 × height^0.725 × weight^0.425. Usually within ~2% of Mosteller.
~1.7 m² average adult; most are 1.5–2.1 m². Rises with height and weight.
Mosteller is the common default; Du Bois is the classic alternative. They differ by only 1–2%.