How ideal weight is calculated
There isn't one single "correct" ideal weight formula — throughout the 20th century, different researchers proposed their own formulas, all based on height (adjusted by sex), without accounting for body composition (muscle vs. fat), age or bone structure. That's why this calculator shows the 4 most cited formulas side by side, plus their average, to give a reference range rather than one rigid number.
The 4 formulas
Devine (1974) is the most used in clinical practice (including for medication dosing); Robinson (1983) and Miller (1983) are later revisions of the same idea; Hamwi (1964) is the oldest and tends to give slightly higher values.
These formulas are old population-level estimates and don't account for your individual body composition — they don't replace an evaluation by a doctor or dietitian.
Frequently asked questions
Why do the 4 formulas give different results?
Each was developed in a different decade, using different population data, and uses its own coefficients — the difference between them is usually a few kilos, and none of them is definitively "more correct" than the others.
Should a muscular athlete worry about being "above" the calculated ideal weight?
Not necessarily — these formulas don't distinguish muscle mass from body fat, so a very muscular person often weighs more than the calculated "ideal" without that indicating excess fat. For that, also check our body fat percentage calculator.