Ideal Weight Calculator by Height

The four formulas and why they differ

Each formula starts from a base weight for five feet of height and adds a fixed amount per inch over that. Devine adds 2.3 kg per inch over 5 feet, Hamwi adds 2.7 for men and 2.2 for women, Robinson less, Miller less still - so a tall person sees the disagreement grow with height as the per-inch multipliers compound.

All four were published as bedside guessing rules for dosing, not as health targets, which is exactly why presenting all of them together says more than picking one.

The disagreement between the four is not a bug; it is the honest product of each formula choosing a slightly different base weight and a slightly different per-inch multiplier. Because those add on every inch, the spread widens the taller the figure, which is why the page prints all four and why a single "ideal" number would be an act of selection rather than a measurement.

Two BMI scales is the honest move

The WHO healthy range is 18.5 to 24.9; the WHO Asia-Pacific range for people of South and East Asian descent is 18.5 to 22.9, because the original cut-offs under-detect risk in those populations. The page shows the weight band each range implies at your height, and the ethnicity setting decides which band leads the hero while both stay in the table.

The two bands are computed from the same height using the two BMI cut-offs, so the only difference between them is where the ceiling sits. The Asia-Pacific band exists because the original WHO figures were derived mostly from Western populations, and applying a single cut-off to everybody was known to under-detect risk in parts of the world. Printing both does not mean one is right for you any more than the four formulas do - it is the stack of estimates, not any single line, that the page is asking you to look at.

The same estimates in kilos or pounds

Every formula and every range is computed in kilograms and shown in the unit you choose, with the pounds column always beside the formulas table so the two never drift apart. Switching units changes the label, not the estimate - the same 58.6 kg range is the same 129 lb range, because it is one number printed two ways.

Because the arithmetic is done once in kilograms and the pound column is a pure conversion of that same number, the two can never disagree the way a hand-converted table sometimes does. That matters at a glance: a range quoted in pounds that is not the exact conversion of the kilograms would be a bug nobody could catch without checking the math line by line.

A range is not a recommendation

The same height spans many healthy shapes, compositions and builds. Body frame, muscle mass and age all move where an individual lands, and a doctor looking at the whole picture is the only one who can say where. The page prints this boundary rather than leaving a visitor to read a number as a diagnosis.

The formulas started as bedside tools for estimating drug doses and as shorthand in insurance actuarial tables - they were not health advice written for the person standing in front of a doctor. Body frame, muscle and age are all invisible to a height-only method, so the page intentionally stops at the arithmetic and leaves the placement of an individual body to someone who can see the whole picture.