Adjusted Body Weight (ABW)
Calculate adjusted body weight for obese patients, used in clinical pharmacokinetics for accurate drug dosing.
Results
What is it?
Adjusted Body Weight (ABW) corrects for excess adipose tissue in obese patients using ABW = IBW + 0.4 × (Actual Weight − IBW). It is used in clinical pharmacokinetics to determine more accurate drug doses for medications that partially distribute into fat.
How to use
Enter your actual weight, height, and biological sex. The calculator first derives IBW via the Devine formula, then applies the 0.4 obesity adjustment factor to produce ABW.
Example scenario
A female, 165 cm, 110 kg: IBW ≈ 57.0 kg. ABW = 57.0 + 0.4 × (110 − 57.0) = 57.0 + 21.2 = 78.2 kg. A vancomycin dose would be based on 78.2 kg rather than the full 110 kg.
Pro tip
The 0.4 adjustment factor is most validated for aminoglycosides and vancomycin. Other drugs (e.g., fluoroquinolones, heparin) may use different correction factors — always consult drug-specific pharmacokinetic guidelines.