Adjusted Body Weight Calculator
Calculate adjusted body weight (ABW) for drug dosing in obese patients.
Used in anesthesia and pharmacology for accurate medication calculations.
Your data stays in your browser. We do not store, collect, or transmit any information you enter.
Adjusted Body Weight
Adjusted Body Weight (ABW) is used when actual body weight significantly exceeds ideal body weight, particularly for drug dosing in obese patients.
Formula:
ABW = IBW + 0.4 x (Actual Weight - IBW)
Where:
ABW= Adjusted Body WeightIBW= Ideal Body Weight0.4= correction factor (standard for most drugs)
Ideal Body Weight (Devine formula):
- Males:
IBW (kg) = 50 + 2.3 x (height in inches - 60) - Females:
IBW (kg) = 45.5 + 2.3 x (height in inches - 60)
Imperial to metric: 1 lb = 0.4536 kg, 1 inch = 2.54 cm
When to use ABW:
- Patient"s actual weight exceeds IBW by >20%
- Dosing aminoglycosides (gentamicin, tobramycin)
- Some anesthetic agents
- Certain chemotherapy protocols
Important: This calculator is for educational purposes only. Always verify dosing with a clinical pharmacist and follow institutional protocols.