Ideal body weight calculator (Devine formula)
The Devine ideal body weight (IBW) formula estimates a reference weight from a person's height and sex. Published by Dr. B.J. Devine in 1974, it was built to standardize drug dosing, not to define a "healthy" weight. Clinicians still use it to weight-base medications (for example aminoglycosides), set ventilator tidal volumes, and calculate other IBW-dependent estimates.
How it works
The formula starts from a fixed base weight for a 5-foot (60-inch) adult, then adds 2.3 kg for every inch of height above that. The base differs by sex. Exact equations: men, IBW (kg) = 50 + 2.3 × (height in inches − 60); women, IBW (kg) = 45.5 + 2.3 × (height in inches − 60). It is a linear estimate calibrated for adults 5 feet and taller; below 60 inches it extrapolates and should not be relied on.
Worked example
A man who is 5 feet 10 inches tall is 70 inches. Inches over 60 = 10. IBW = 50 + 2.3 × 10 = 50 + 23 = 73 kg (about 161 lb). A woman of the same height: IBW = 45.5 + 2.3 × 10 = 45.5 + 23 = 68.5 kg (about 151 lb).
Important
Estimate only. This tool is educational and is not medical advice, a diagnosis, or a treatment recommendation. Devine IBW is a drug-dosing / reference construct, not a target or "healthy" weight, and it does not account for body composition, muscle mass, amputation, edema, pregnancy, ascites, or age. It is calibrated for adults 5 feet (60 in) and taller and is not validated for children, adolescents, or shorter stature, where it extrapolates and can materially mis-estimate. Do not use it to start, stop, or self-adjust any medication dose, ventilator setting, or fluid calculation. Actual drug dosing (for example aminoglycosides), tidal-volume, and renal-function decisions must be made by a licensed clinician using measured weight, labs, and clinical judgment. Talk to your doctor or pharmacist before acting on any number here.