Ideal Body Weight Calculator

Calculate ideal body weight using Devine formula (IBW = 50kg + 2.3kg per inch over 5ft for males) — used for ventilator tidal volume and drug dosing.

Sex
Height unit
Height (cm)
70.5 kg
Devine IBW — recommended range 68.7–72.0 kg across methods
IBW by method
MethodIBW (kg)Formula
Devine70.5base + 2.3 kg/in over 5 ft
Robinson68.9base + 1.9/1.7 kg/in over 5 ft
Miller68.7base + 1.41/1.36 kg/in over 5 ft
Hamwi72.0base + 2.7/2.2 kg/in over 5 ft
Recommended range68.7–72.0kg
Clinical Guidance

Ideal body weight estimates a healthy weight for a given height and sex. The Devine formula is the most widely used for drug dosing and ventilator tidal-volume sizing; Robinson, Miller and Hamwi are alternative published methods. All four are expressed as a base weight plus an increment per inch of height above 5 ft (60 in). For heights at or below 5 ft the base weight applies.

IBW is an estimate, not a diagnosis. Actual healthy weight varies with frame size, muscle mass and age. Always use clinical judgment and local protocols when dosing medications.

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How It Works

Calculate ideal body weight using Devine formula (IBW = 50kg + 2.3kg per inch over 5ft for males) — used for ventilator tidal volume and drug dosing

Each component has a specific meaning:

  • Devine formula (IBW = 50kg + 2 — The devine formula (ibw = 50kg + 2 recorded for the scenario being assessed.

Note: Interpret the ideal body weight result against the thresholds and context described above.

How to Use

Enter the Devine formula (IBW = 50kg + 2 for the scenario you are assessing. Calculate ideal body weight using Devine formula (IBW = 50kg + 2.3kg per inch over 5ft for males) — used for ventilator tidal volume and drug dosing. Use the ideal body weight result to inform your calculation.

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