Body Metrics

Adjusted Body Weight Calculator

Ideal weight plus 40% of the excess; used for dosing and creatinine clearance in obese patients.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

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Formula

IBW + 0.4 * (Actual - IBW)

How it is used

• AdjBW = IBW + 0.4 × (actual − IBW), commonly used once actual weight is well above ideal (often over 120–130% of IBW).
• Used for aminoglycoside dosing and for Cockcroft–Gault in obesity; check each drug’s reference, since some use actual or ideal weight instead.
• Ventilator tidal volume uses predicted body weight, never adjusted or actual weight.

Same formula as the app. Open it in the web app.

Related calculators

• BMI
• BSA (Mosteller)

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.