Ideal Weight Calculator
0 lb ideal body weight (Hamwi)
Why This Calculator Shows Four Different Numbers
There is no single, universally agreed-upon "ideal weight" formula. This calculator shows the four most widely cited height-based formulas from clinical and pharmacology literature: the Hamwi method (1964), the Devine formula (1974, still the standard used for drug-dosing calculations in medicine), the Robinson formula (1983), and the Miller formula (1983). Each was built from slightly different reference populations, so they produce a range rather than one definitive answer — the spread between them is itself informative. All four use only height and biological sex as inputs; none of them account for muscle mass, frame size, or body composition.
The Formulas Used
Each formula starts from a base weight for 5 feet of height and adds a fixed amount per inch over 5 feet:
- Hamwi: Men: 106 lb + 6 lb/inch over 5 ft. Women: 100 lb + 5 lb/inch over 5 ft.
- Devine: Men: 50 kg + 2.3 kg/inch over 5 ft. Women: 45.5 kg + 2.3 kg/inch over 5 ft (converted to pounds).
- Robinson: Men: 52 kg + 1.9 kg/inch over 5 ft. Women: 49 kg + 1.7 kg/inch over 5 ft.
- Miller: Men: 56.2 kg + 1.41 kg/inch over 5 ft. Women: 53.1 kg + 1.36 kg/inch over 5 ft.
For a broader, less formula-specific perspective, the healthy weight calculator shows the full weight range associated with a normal BMI, and the BMI calculator tells you where your current weight falls on that scale.
A Number on a Chart Isn't a Diagnosis
These formulas were designed decades ago as rough clinical shorthand, not as a personal target to chase. Athletes, people with more muscle mass, and people of different body frame sizes can be perfectly healthy well outside these numbers. This tool is for general education only and is not medical advice — talk to a doctor or registered dietitian before making decisions about your weight or health.
Frequently Asked Questions
Why do the four formulas give different results?
Each formula (Hamwi, Devine, Robinson, and Miller) was derived from a different reference population and published in a different decade, so they use slightly different base weights and per-inch increments. None is more 'correct' than the others — together they show a reasonable range rather than one precise number.
Does ideal weight account for muscle mass or body frame?
No. These formulas only use height and biological sex, so they can understate a healthy weight for muscular or large-framed individuals and overstate it for smaller-framed individuals. For a composition-aware view, pair this with the body fat calculator or lean body mass calculator rather than relying on height alone.