⚖️ Ideal Weight Calculator
Calculate your healthy weight range based on established medical formulas and BMI standards.
Four formulas, four answers, and what to do with the spread
There is no single ideal weight, and the four formulas most commonly used disagree with each other by several kilograms. They were not derived from health outcomes; they came from medication dosing and insurance tables in the mid-twentieth century. Knowing where they came from is the key to using them sensibly.
The four formulas
| Formula | Year | Men | Women |
|---|---|---|---|
| Devine | 1974 | 50.0 kg + 2.3 kg per inch over 5 ft | 45.5 kg + 2.3 kg per inch over 5 ft |
| Robinson | 1983 | 52 kg + 1.9 kg per inch over 5 ft | 49 kg + 1.7 kg per inch over 5 ft |
| Miller | 1983 | 56.2 kg + 1.41 kg per inch over 5 ft | 53.1 kg + 1.36 kg per inch over 5 ft |
| Hamwi | 1964 | 48.0 kg + 2.7 kg per inch over 5 ft | 45.5 kg + 2.2 kg per inch over 5 ft |
The Devine formula, still the most widely cited, was published to calculate drug dosages, not to advise patients on weight. None of the four adjusts for frame size, muscle mass or body composition, and all of them are built around a 5-foot baseline with a linear increment that becomes unreliable at the extremes of height.
How much they disagree
| Formula | Result |
|---|---|
| Devine | 75.4 kg |
| Robinson | 73.4 kg |
| Miller | 71.7 kg |
| Hamwi | 77.7 kg |
| WHO healthy BMI range (18.5–24.9) | 60.0 – 80.7 kg |
A six-kilogram spread between the formulas, inside a twenty-kilogram healthy BMI range. That spread is the honest answer: healthy weight is a band, not a point, and anywhere inside the band can be right depending on build and composition.
Frame size
A rough adjustment uses wrist circumference relative to height. For a man under 1.65 m, a wrist under 16.5 cm suggests a small frame and over 19 cm a large one; for a woman of the same height, under 14 cm and over 16.5 cm respectively. A small frame justifies the lower end of the range and a large frame the upper, typically shifting the target by about 10%.
Why the number matters less than you think
Research consistently finds that fitness, waist circumference and metabolic markers predict health outcomes better than weight does. Someone five kilos above their calculated ideal weight who exercises regularly and has a normal waist measurement is in better shape, by any outcome that matters, than someone at exactly their ideal weight who is sedentary.
If you are using this to set a goal, use the healthy BMI range for your height as the band and pick a point inside it that you can reach and hold without a restrictive diet. A weight you cannot maintain is not a target.
A worked example
A woman of 163 cm (5 ft 4 in). Devine gives 54.7 kg, Robinson 55.8 kg, Miller 58.5 kg and Hamwi 54.3 kg, averaging 55.8 kg. Her healthy BMI range is 49.2 kg to 66.1 kg. With a wrist of 17 cm, she has a large frame for her height, which points to the upper half of that range, somewhere around 58 to 62 kg, rather than the formula average.
This page explains published formulas and population-level ranges. It is general information, not medical advice, and it cannot account for your individual health. Talk to a doctor or a registered dietitian before changing how you eat, train or treat a condition.
Frequently Asked Questions (FAQs)
Which ideal weight formula is the most accurate?
None of them is accurate in the way the question implies, because none was validated against health outcomes. Robinson and Miller are generally considered the better-behaved of the four. The healthy BMI range for your height is a more defensible target than any single formula result.
Why do the formulas give different answers for men and women?
They were built on observed average body composition, and women naturally carry a higher proportion of essential fat and generally less muscle mass at the same height. The constants in each formula encode that difference, crudely.
Do these formulas work for very tall or very short people?
Poorly. All four are linear extensions from a 5-foot baseline, so they drift at the extremes, overestimating for very tall people and underestimating for very short ones. Below about 1.50 m or above 1.95 m, use the BMI range instead.
Should athletes use this calculator?
No. Every one of these formulas assumes average body composition, so a muscular athlete will be told they are well over their ideal weight when they carry very little fat. Body fat percentage and performance measures are the right tools there.
How is ideal weight used in medicine?
Mainly for drug dosing. Some medications distribute through lean tissue rather than fat, so dosing by actual body weight would overdose a heavier patient. The Devine formula exists for exactly this purpose, which is why it appears in clinical software far more often than in weight-loss advice.
What about children?
None of these apply. Children's healthy weight is assessed against age and sex-specific growth percentile charts, which account for developmental stage. A paediatrician should interpret those, not an adult formula.