Medical Calculator

Ideal Body Weight & Adjusted Body Weight Calculator

Uses the Devine (1974) formula to calculate IBW and AdjBW for clinical dosing, ventilator settings, and nutritional assessment.

Patient Information
Units
Male
Female
cm
kg
Ideal Body Weight (Devine)
kg
Normal range: — to — kg (±10%)
BMI
kg/m²
Adjusted BW
kg
% Over IBW
%
Actual BW
kg
Weight vs. Ideal Body Weight
IBW −10% IBW IBW +30%+
About This Calculator
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Formulas used

Devine Formula (1974) — most widely adopted in clinical settings:

Male: IBW = 50 + 2.3 × (height_in − 60)

Female: IBW = 45.5 + 2.3 × (height_in − 60)

Adjusted Body Weight — applies when ABW > 130% of IBW:

AdjBW = IBW + 0.4 × (ABW − IBW)

BMI: weight (kg) ÷ height² (m)

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Clinical use cases

IBW and AdjBW are used to determine dosing for:

  • Aminoglycosides (gentamicin, tobramycin, amikacin)
  • Vancomycin loading and maintenance dosing
  • Mechanical ventilation tidal volume (6 ml/kg IBW)
  • Chemotherapy dosing (some agents)
  • Nutritional and caloric requirements
  • Anesthesia and sedation calculations
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Limitations & caveats

The Devine formula has known limitations:

  • Not validated for patients under 5 ft (152.4 cm)
  • Does not account for body composition or muscle mass
  • AdjBW correction factor (0.4) has variable evidence
  • Alternative formulas: Hamwi, Robinson, Miller

Always combine with clinical judgment. This tool does not replace physician assessment.

Medical Disclaimer: This calculator is for informational and educational purposes only. Results must be re-checked and should not be used alone to guide patient care, nor should they substitute for clinical judgment. Always consult a qualified healthcare professional.