The Devine formula gives a quick estimate of ideal body weight from height and sex. Hospitals created it in the 1970s to dose medications, not to judge appearances, and that origin explains both its usefulness and its limits.
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Scientific references
Born in the pharmacy, not the gym
Dr BJ Devine published his formula in 1974 to standardize gentamicin dosing. Antibiotics and many other drugs distribute unevenly into fat tissue, so dosing by actual weight in a heavy patient overdoses the drug, while dosing ideal weight keeps concentrations in the therapeutic window. The formula starts at 50 kg for men at five feet and adds 2.3 kg per inch beyond, with women starting at 45.5 kg. Converted to metric it does the same job from 152 cm upward.
Why the number survives
Simplicity keeps Devine alive. Ventilator settings, chemotherapy calculations, and nutrition planning all still reference it, and generations of clinicians carry the numbers in their heads. The formula also correlates loosely with the weight range associated with lowest mortality in older actuarial tables, which gave it a second life as a wellness target long after its pharmaceutical birth.
Honest weaknesses
The formula knows nothing about you. It ignores frame size, muscle mass, age, and ethnicity, and it drifts unrealistically low for short adults and high for tall ones. A muscular 180 cm man lands at 77 kg by Devine, which may sit far from his healthy functional weight. Modern alternatives adjust with BMI based targets or frame corrections, and many protocols now cap dosing weight with an adjustment factor in obesity rather than trusting ideal weight alone.
How to use the estimate sanely
Think of the output as a coordinate on a map rather than a destination. If your current weight sits near it and you feel strong and well, fine. If it sits far away, let waist to height ratio and body composition guide the target instead of a 1974 constant. And if the number appears on a hospital chart, recognize it for what it is, a dosing convention doing its quiet job in the background.