Ideal Weight Calculator

The most defensible answer to "what should I weigh" is a range, not a figure. This page shows the weights that place your BMI between 18.5 and 24.9 — the WHO normal band for adults — by running the BMI formula backwards: weight = BMI × height². At 1.75 m that is 18.5 × 1.75² to 24.9 × 1.75², roughly 56.7 to 76.3 kg. The span is wide, and it is wide for a reason. The band it comes from was drawn across a population, and the whole of it is treated identically. No point inside the range is more "ideal" than any other point, and where you sit within it tells you nothing on its own.

When people want one figure instead of a range, the classic is the Devine formula, published in 1974: 50 kg for men or 45.5 kg for women at five feet of height, plus 2.3 kg for every inch above that. It matters what it was built for. Devine was proposed as a drug-dosing convention — a standardized way of scaling medication doses to body size — not as a health target, and certainly not as an aesthetic one. It was never validated as the weight at which a person is healthiest, and it is not evidence of anything about you. It is also a straight line, which is a poor model of how bodies scale. Compared with the BMI-derived band, it produces conspicuously low figures for tall people, and the underlying rule has nothing at all to say below five feet.

That last point shows up directly in this calculator. The Devine rule adds 2.3 kg per inch above 60 inches, so below that height there is nothing left to add and the formula collapses to its base value — 50 kg for men, 45.5 kg for women — no matter how much shorter the person is. So if you entered a height under about 152 cm, the Devine figure displayed is the formula's floor rather than a meaningful estimate for you. The BMI-derived range above it still scales properly with height and is the better reference in that case. This is not an arithmetic error. It is the shape of a 1974 dosing rule being asked a question it was never designed to answer.

None of these figures know anything about body composition. Muscle is denser than fat tissue, so a well-trained person can sit above the band while carrying very little fat, and someone with little muscle can sit comfortably inside it while carrying a great deal. Frame size, bone density and how much water the body is holding all move the scale too. Weight also changes for reasons that have nothing to do with fat: hydration, sodium, glycogen stores, gut contents and, for some people, the menstrual cycle. Day-to-day swings of a kilogram or more are ordinary and are not information. What does add information alongside weight is waist circumference, which speaks to fat distribution, and clinical markers — blood pressure, blood glucose, lipids — which are closer to what health actually turns on.

These values are for non-pregnant adults. Children and teenagers are assessed on age- and sex-specific growth charts, never adult bands. In pregnancy, weight is followed against pre-pregnancy BMI through prenatal care. In later life the discussion around an appropriate BMI shifts upward, and age-related height loss distorts the calculation on top of that. A plain statement is warranted here, because it is the question this page attracts: a weight is not an appearance target. If a number here worries you, or if you find yourself pursuing a figure rather than a state of health, that is a conversation to have with a physician or a registered dietitian — and it is worth having early rather than late. This page inverts two published formulas and explains what each was built for. It does not tell anyone what to weigh, what to eat or how to train.