How Your Ideal Weight Is Estimated by Four Classic Formulas

Four decades-old clinical formulas — Devine, Robinson, Miller, and Hamwi — each estimate ideal bodyweight from height and sex using their own base weight and slope, and averaging all four gives a single reference point.

By CalcuTool Editorial Team

Reviewed 14-09-2026

The shared shape: base weight plus a per-inch slope

All four formulas follow the same pattern — a base weight for exactly 5 feet (60 inches) of height, plus a fixed amount added for every inch above that, with different constants for men and women.

A worked example: a man at 175cm

175cm converts to roughly 68.9 inches, about 8.9 inches over the 60-inch base. The four formulas give: Devine 70.5kg, Robinson 68.9kg, Miller 68.7kg, and Hamwi 72.0kg — a spread of 3.3kg between the lowest and highest estimate. Averaging all four gives 70.0kg.

A second example, a woman at 160cm

For a woman at 160cm: Devine 52.4kg, Robinson 54.1kg, Miller 57.2kg, and Hamwi 52.1kg — averaging to 53.9kg. Miller's estimate here is noticeably higher than the other three, illustrating how much the four formulas can disagree even for the same height.

Why four different formulas exist at all

Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) were each developed independently, mostly for calculating medication doses — not as fitness or aesthetic targets. None is more "correct" than the others; averaging across all four smooths out their individual disagreement into one usable reference figure.

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