Compare four classic ideal-weight formulas with the healthy BMI range for your height, in your browser.
There is no single ideal weight, and this calculator is built to show you why. Give it your sex and your height and it returns two very different answers side by side: the range that corresponds to a healthy body mass index — a BMI between 18.5 and 24.9 — and the single numbers produced by the four ideal-weight formulas that have circulated in clinics and gyms since the 1960s. For a man of 1.75 m the BMI range runs from about 56.7 kg to 76.3 kg, while Devine says 70.5 kg, Robinson 68.9 kg, Miller 68.7 kg and Hamwi 72.0 kg. Same body, four different targets.
All four formulas share the same shape: a base weight for someone five feet tall, plus a fixed number of kilos for every inch above that. They differ only in the constants, because each was fitted to a different sample in a different decade — Hamwi in 1964, Devine in 1974, Robinson and Miller in 1983. Devine's version was never meant to describe a healthy body at all: it was written to size drug doses, where a rough proxy for lean mass is more useful than an actual weight. The BMI range works the other way round, starting from a ratio rather than a target: it multiplies 18.5 and 24.9 by your height in metres squared, which is why it gives you a band instead of a point.
Treat every number here as a reference, not a goal. The formulas were built on adults between roughly 1.52 m and 1.90 m, they offer only two sexes, and outside that range they extrapolate along a straight line that quickly stops making sense. None of them — and neither does BMI — can tell muscle from fat, which is why a trained athlete and a sedentary adult of the same height and weight can be in completely different shape. Waist circumference, blood work, strength and sleep say far more than any of these targets. This tool is informational, it does not replace a doctor or a nutritionist, and every calculation runs in JavaScript on your own device.
Each classic formula starts from a base weight and adds a fixed amount per inch above 5 ft (152.4 cm): Devine 50.0 kg + 2.3 kg/in for men and 45.5 + 2.3 for women; Robinson 52.0 + 1.9 and 49.0 + 1.7; Miller 56.2 + 1.41 and 53.1 + 1.36; Hamwi 48.0 + 2.7 and 45.5 + 2.2. The healthy range comes from BMI instead: weight = BMI × height², with 18.5 and 24.9 as the bounds.
There is no single answer, and the reference most used today is a range rather than a number: the weights that give a BMI between 18.5 and 24.9, which at 1.75 m runs from about 56.7 kg to 76.3 kg. The four classic formulas each return one point inside or near that band, and they disagree with one another by three to four kilos.
For everyday purposes, none of them: use the BMI range. The formulas survive mainly in clinical settings, especially Devine, which is still used to derive drug doses and ventilator settings from height.
Because each was fitted to a different population sample in a different decade, with no shared definition of what "ideal" means. They all use the same structure — a base weight plus a fixed amount per inch above five feet — and only the constants change.
No. Muscle is denser than fat, so a well-trained person often weighs far more than any of these formulas suggest while being perfectly healthy. Neither the formulas nor BMI can distinguish one tissue from another.
No. The calculation runs 100% in JavaScript on your device. Nothing you type is transmitted or stored.
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