Ideal weight calculator
Devine published his formula in 1974 to calculate drug dosages, not to advise anyone on their weight. Hamwi wrote his a decade earlier for insulin dosing in diabetes. They persist as "ideal weight" formulas through habit rather than evidence, and none of them accounts for build, muscle or age. The healthy BMI range at the bottom is a wide band for a reason — it is closer to how bodies actually vary.
There is no single ideal weight. These formulas were written for clinical dosing, not for health advice, and they ignore build, muscle and age entirely. The healthy BMI range is a better guide, and a doctor is better than either.
The four common formulas — Devine, Robinson, Miller and Hamwi — give answers within a few kilograms of each other. For a 175 cm man they land around 70 to 73 kg, inside a healthy BMI range of 56.7 to 76.3 kg, which is considerably wider.
How to read an ideal weight figure
The gap between the point estimates and the BMI range is the whole story. The formulas produce a single figure because a dosing calculation needs one; health does not work that way. A healthy weight at 175 cm spans nearly twenty kilograms, and where an individual sits within that depends on frame, muscle and what they can maintain. Anyone using an ideal weight figure as a target is choosing an arbitrary point in a wide band and calling it correct.
Questions
Devine is the best known: 50 kg for men or 45.5 kg for women, plus 2.3 kg per inch over five feet.