About this tool
"Ideal body weight" is not a single scientific number — it is a family of rough heuristics that clinicians and dietitians have used since the mid-20th century, mostly to get a quick reference weight for drug dosing or nutrition planning. All four formulas below share the same basic shape: a base weight for someone 5 feet (60 inches) tall, plus a fixed amount added for every inch above that. They were fit to different datasets at different times — Hamwi (1964) as a simple bedside rule, Devine (1974) which became the de-facto clinical standard, and the Robinson and Miller revisions (both 1983) that updated the coefficients against newer actuarial and insurance data.
Because each formula was derived independently, they routinely disagree by several kilograms for the same height and sex — which is itself informative: it shows how much these numbers are population averages, not individual targets. None of the four accounts for muscle mass, bone density, body frame, age, or fitness level, so a muscular athlete and a sedentary person of identical height will get the identical "ideal" number despite having very different healthy body compositions. Use this calculator to see the range these formulas produce, not as a target to hit — and talk to a doctor or dietitian for guidance that accounts for your actual body composition and health history.
Frequently asked questions
Why do the four formulas give such different results?
Each formula was independently derived by different researchers, in different decades (1964-1983), often from different reference population datasets and different clinical goals (e.g. drug-dosing weight estimates vs. general health guidance) — there was never a single unified scientific consensus on "ideal weight" the way there is for something like blood pressure ranges. Seeing all four together is actually the most honest way to present this: it shows you the real spread of expert opinion rather than presenting one arbitrary number as scientific fact.
Should I try to hit exactly one of these numbers?
No — these formulas ignore individually important factors like muscle mass, bone density/frame size, and overall body composition, so a bodybuilder and a sedentary person of the same height would get identical "ideal weight" numbers despite having very different healthy body compositions. Use the range these four formulas collectively suggest as rough context, not a strict target — a healthcare provider who can assess your actual body composition and health markers gives far more individually meaningful guidance than any formula based on height alone.