Ideal, adjusted and lean body weight

Oncology & dosing

Which weight to dose on changes by drug. Aminoglycosides use adjusted weight; many anaesthetic and critical-care drugs use ideal or lean weight.

What you enter

Height (cm or in)
Actual weight (kg or lb)
Sex: Male / Female

FORMULAIBW (Devine): M 50 + 2.3 kg per inch over 5 ft; F 45.5 + 2.3 per inch; AdjBW = IBW + 0.4 × (actual − IBW); LBW (Janmahasatian): M 9270×W ÷ (6680 + 216×BMI); F 9270×W ÷ (8780 + 244×BMI)

SourceDevine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650-5; Janmahasatian S et al. Quantification of lean bodyweight. Clin Pharmacokinet 2005;44:1051-65ReviewedFormula and thresholds checked against the source on 2026-08-22. If the source updates, this line will say so.