Patient Data

Metric Imperial

Clinical Metrics

Body Surface Area (Mosteller)
1.88 sq m
  • Body Mass Index (BMI) 22.9 kg/sq m
  • Ideal Body Weight (IBW) 68.8 kg
  • Adjusted Body Weight (ABW) 70.0 kg
  • BSA (from Adjusted BW) 1.88 sq m

Comparative BSA Formulas

  • Du Bois 1.86 sq m
  • Haycock 1.86 sq m
  • Gehan & George 1.83 sq m
  • Boyd 1.90 sq m

This page shows how to calculate BSA from height and weight. It includes two common formulas: Mosteller and Du Bois. Use it for quick estimates in clinics, pharmacy, and nutrition.

Inputs

  • Height (H): centimetres (cm)
  • Weight (W): kilograms (kg)

Formulas

Mosteller (simple and popular)

BSA (m²) = √( (H × W) ÷ 3600 )

Du Bois & Du Bois (classic)

BSA (m²) = 0.007184 × H^0.725 × W^0.425

How to use

  1. Convert height to cm and weight to kg.
  2. Pick a formula. Mosteller is easy and widely used.
  3. Plug in H and W. Compute BSA in square metres (m²).
  4. Round to two decimals for reports (for example 1.73 m²).

Worked examples

Example 1 — Mosteller

H = 170 cm, W = 65 kg.

BSA = √((170 × 65) ÷ 3600) = √(11050 ÷ 3600) = √(3.0694) ≈ 1.75 m²

Example 2 — Du Bois

H = 160 cm, W = 70 kg.

BSA = 0.007184 × 160^0.725 × 70^0.425 ≈ 1.74 m²

Unit tips

  • If height is in inches: cm = inches × 2.54
  • If weight is in pounds: kg = lb ÷ 2.20462
  • Always compute BSA in m².

Why BSA matters

  • Drug dosing (some chemo and pediatric doses).
  • Kidney and liver function indexing.
  • Cardiac output indexed to body size.

Notes and limits

  • Formulas give estimates, not exact surface area.
  • Do not use BSA alone for medical decisions. Follow local protocols.
  • For very small or very large body sizes, formulas may differ more.

Common mistakes

  • Mixing units (inches with cm, pounds with kg).
  • Rounding too early. Round at the end.
  • Reporting BSA without decimals (lose precision). Use two decimals.

Quick reference

  • Mosteller: √(H×W/3600)
  • Du Bois: 0.007184 × H^0.725 × W^0.425
  • Typical adult BSA: about 1.6–2.2 m²

FAQ

Which BSA formula should I use?

Mosteller is simple and common. Du Bois is classic and also widely used. Many clinics accept either if used consistently.

Can I enter height in metres?

Yes. Convert first: cm = metres × 100. Then use the formula.

Does BSA change with weight loss?

Yes. BSA depends on height and weight. It will change as weight changes.

What precision is best?

Two decimals (for example 1.73 m²) are standard.

Is BSA the same as BMI?

No. BMI is weight/height². BSA estimates total body surface area. They answer different questions.