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Adjusted Body Weight (Dosing Weight)

Adjusted body weight = IBW + 0.4 × (actual weight − IBW), used for dosing drugs such as aminoglycosides and for Cockcroft-Gault in obesity, typically when actual weight exceeds 120% of IBW.

  • Weight (kg or lb)
  • Height (cm or m or in)
  • Sex: Male; Female
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Formula

AdjBW = IBW + 0.4 × (TBW − IBW); IBW (Devine) = 50 (men) / 45.5 (women) + 2.3 × (inches over 60)

Clinical pearls

  • The 0.4 factor was derived for aminoglycosides (Traynor 1995 found 0.43); other drugs may use different weights.
  • Check the specific drug monograph: some use IBW, some AdjBW, some actual or lean body weight.

Examples

adjusted body weight 120 kg 180 cm maledosing weight for obese woman 110 kg 5'4"

FAQ

When do you use adjusted body weight?

Usually when actual body weight exceeds about 120% of ideal body weight, for drugs like aminoglycosides and for Cockcroft-Gault creatinine clearance.

Evidence

  1. Traynor AM, Nafziger AN, Bertino JS Jr. Aminoglycoside dosing weight correction factors for patients of various body sizes. Antimicrob Agents Chemother 1995;39:545–8.
  2. Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother 2000;34:1066–9.

General & Anthropometrics · Reviewed 2026-10-14 · Methodology