Ideal Weight Calculator
Four classic formulas side-by-side, plus a healthy BMI range.
Why Four Different Formulas?
"Ideal weight" is not a single objective number — every formula reflects assumptions made by its author for specific contexts (medication dosing, insurance underwriting, life-expectancy tables). The four formulas here have all been in active clinical use. The Wikipedia overview of ideal body weight formulas covers their history.
| Formula | Year | Original Purpose |
|---|---|---|
| Hamwi | 1964 | Quick clinical rule for nutrition / dietetics |
| Devine | 1974 | Aminoglycoside antibiotic dosing |
| Robinson | 1983 | Refinement of Devine for medication dosing |
| Miller | 1983 | Alternative life-table-based estimate |
5'10" (178 cm) male, four formulas, four numbers
| Formula | Result |
|---|---|
| Hamwi | 77.0 kg (170 lb) |
| Devine | 72.6 kg (160 lb) |
| Robinson | 75.0 kg (165 lb) |
| Miller | 70.4 kg (155 lb) |
| Healthy BMI range | 58.7-79.1 kg (129-174 lb) |
Spread between formulas is ~6.5 kg (14 lb) — for the same person. None is "the right answer." The BMI range is broader because it acknowledges natural human variation in healthy body weight.
The BMI Range Is Usually the Better Target
For most adults, the healthy-weight range derived from a BMI of 18.5-24.9 is more useful than any single "ideal weight" number. It acknowledges that healthy weight depends on body composition, frame size, and individual variation. See our BMI calculator for the range specific to your height.
None of These Capture Muscle Mass
All four formulas assume average body composition. A muscular athlete will exceed every "ideal" weight estimate while being healthier than someone at the prescribed number. Bodybuilders, powerlifters, and many soldiers register as "overweight" by BMI and "above ideal" by every formula here — yet have lower body fat % and better metabolic health than most people in the "ideal" range.
Frequently Asked Questions
Which formula should I trust?
None individually — they're all approximations from different eras for different purposes. The healthy BMI range (or our body fat calculator) is more useful for most personal-health decisions.
Why is medication dosing based on Devine?
Devine's formula was developed specifically for aminoglycoside antibiotic dosing in 1974. It's still widely used in clinical pharmacy for fat-insoluble drugs where dosing by total body weight would be unsafe in obese patients.
Do these work for women equally well?
The formulas have sex-specific constants but were validated primarily on male populations decades ago. Modern dietetics typically uses BMI range or body-fat % instead.