Formulas (Devine)

• Male: IBW = 50 kg + 2.3 kg per inch over 5 ft.
• Female: IBW = 45.5 kg + 2.3 kg per inch over 5 ft.
• Adjusted BW = IBW + 0.4 × (actual − IBW), used when actual > IBW.

Worked example

Male, 180 cm (70.9 in), actual 100 kg → IBW = 50 + 2.3 × 10.9 = 75.0 kg; AdjBW = 75 + 0.4 × 25 = 85.0 kg.

Notes

• Which weight to dose on (actual, ideal, adjusted) depends on the drug – follow the drug reference.
• Devine assumes height ≥ 5 ft; below that, other methods apply.

Reference

Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650-655.

Educational use only – for checking and learning medication math. Always verify doses against the order, the drug reference and a pharmacist. Reviewed 2026-08-23.