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Ideal Weight Calculator

Calculators · Added 15 August 2026

Compare what the four standard ideal body weight formulas give for your height, alongside the healthy BMI range. They disagree by several kilograms, and none of them was designed to tell a person what to weigh — they come from clinical medicine, where a height-based reference weight is needed for drug dosing.

Units
Sex
cm

How to use the ideal weight calculator

  1. 1Choose metric or imperial units.
  2. 2Select sex and enter your height.
  3. 3Read the four formula results and the spread between them.
  4. 4Compare against the healthy BMI range, which is a range rather than a single number.
  5. 5Treat the whole thing as context, not a target.

Examples

A man of 5 ft 10 in

Input
178 cm, male
Result
Devine 73.0 kg · Robinson 71.0 kg · Miller 70.3 kg · Hamwi 75.0 kg

Nearly 5 kg between the highest and lowest.

A woman of 5 ft 5 in

Input
165 cm, female
Result
Devine 57.0 kg · Robinson 57.5 kg · Miller 59.9 kg · Hamwi 56.5 kg

The formulas cluster more closely at this height than at the extremes.

The BMI range for comparison

Input
178 cm
Result
58.6 – 78.9 kg

A twenty-kilogram range — considerably wider, and more honest, than any single figure.

About the ideal weight calculator

A clinical tool doing a job it was not built for

The phrase 'ideal body weight' is unfortunate, because it implies a target when what these formulas produce is a reference. In clinical use the distinction is clear: an ideal body weight is a standardised figure derived from height, used because certain drugs and ventilator settings scale with lean mass rather than total mass. Nobody in that context believes the number describes what a patient should weigh.

Outside the clinic the phrase gets read literally, and a figure calculated for pharmacokinetics becomes a personal goal. That is a misuse of the tool, and the disagreement between the four formulas is a useful demonstration of why — if they were measuring something real about an individual, they would agree with each other.

All four share the same structure, a base weight at five feet plus a fixed amount per inch, which is a very strong simplifying assumption. It treats the relationship between height and appropriate weight as linear, identical for everyone of a given sex, and independent of everything else about a person. That was a reasonable simplification for its purpose and is a poor description of human bodies.

What actually predicts health

Weight for height is a weak proxy for the things that matter. Body composition — how much of the weight is muscle against fat — matters considerably more, and where fat is carried matters more still. Visceral fat around the organs carries substantially more metabolic risk than subcutaneous fat, and two people at identical weight and height can differ markedly in both.

This is why waist circumference and waist-to-height ratio have gained ground as simple measures. They capture central adiposity, which weight alone cannot, and they need only a tape measure. A common rule of thumb is keeping waist circumference under half of height, which has performed well against health outcomes in several large studies and requires no formula at all.

Fitness is the other variable that weight-based measures miss entirely. Cardiorespiratory fitness is a strong independent predictor of mortality, and improvements in it produce health benefits whether or not weight changes. Someone active and stable at a weight above their calculated 'ideal' may well be in better health than someone sedentary at it.

Using this page sensibly

The most useful thing on this page is probably the disagreement itself. Four formulas produced by careful clinicians, all still in use, giving answers five kilograms apart for the same person, is a clear signal about how much precision this concept supports. A number presented alone would have implied a certainty that does not exist.

The healthy BMI range is offered alongside because a range is the appropriate shape for the answer, and because it is what health authorities actually use for population guidance. Even so, it is a screening tool for populations rather than a diagnosis for individuals, and it carries its own well-documented limitations around muscle mass and ancestry.

For anything that actually matters — a weight that concerns you, a change you want to make, a health condition affected by weight — this page is not the right source. Speak to a doctor or a registered dietitian, who can take account of your history, body composition, activity and medical circumstances, none of which a formula based on height alone can see.

Frequently asked questions

Which formula is the right one?
None of them is right in the sense the question implies. All four are height-based reference weights from clinical medicine, fitted decades ago, and they disagree with each other by several kilograms. Devine is the most widely implemented, largely because it came first and got embedded in clinical software. If you want a single reference, the healthy BMI range is a better one — because it is a range, which is a more honest shape for this question.
What were these formulas actually created for?
Drug dosing, mostly. Devine's 1974 formula was devised for calculating gentamicin doses, where dosing on total body weight over-doses people carrying more fat, since the drug distributes in lean tissue. Similar reference weights are used for ventilator tidal volume settings and other clinical calculations. They were never intended as personal weight targets, and using them as one applies a tool well outside its purpose.
Why do they all ignore body build?
Because they were designed to be simple and consistent rather than individually accurate — a clinical reference weight needs to be reproducible from a single measurement anyone can take. The consequence is that a heavily muscled athlete and a sedentary person of identical height receive identical answers, which is obviously wrong for at least one of them. Frame size, muscle mass, bone density and age are all ignored entirely.
Why do results below five feet come with a warning?
Because every one of these formulas is defined as a base weight at exactly five feet plus an increment per inch above it. Below that height they are extrapolating past the data they were fitted to, and the linear increment has no evidence behind it in that range. The figures still compute, but they should carry less weight than the BMI range there.
Is the healthy BMI range better?
It is a more appropriate shape for the question, since it gives a range rather than a point, but it has real limitations of its own. BMI does not distinguish muscle from fat, which is why very muscular people are frequently misclassified, and the standard thresholds were derived largely from European-ancestry populations — several health authorities apply lower cut-offs for people of South Asian and East Asian descent. The BMI calculator on this site covers this in more detail.

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