"Ideal weight" isn't one universally agreed number â it's an estimate, and there are actually four different classic formulas that each answer it slightly differently. All four were built for the same original purpose, which explains both their usefulness and their limits.
Where These Formulas Came From
Devine, Robinson, Miller and Hamwi were developed decades ago for clinical use, not as fitness or aesthetic targets. Hamwi's formula (1964) came from diet planning for people with diabetes; Devine's (1974) was published to estimate body weight for calculating drug doses â a use it still has in hospitals today; Robinson and Miller (1983) refitted the same idea to insurance-company height and weight tables.
How They're Calculated
| Formula | Male Base (5ft/152cm) | Added Per Inch Over |
|---|---|---|
| Devine (1974) | 50 kg | +2.3 kg |
| Robinson (1983) | 52 kg | +1.9 kg |
| Miller (1983) | 56.2 kg | +1.41 kg |
| Hamwi (1964) | 48 kg | +2.7 kg |
Each starts from a base weight at 5 feet (152cm) and adds a fixed amount per inch of height above that â the four formulas differ slightly in both their base and their per-inch increment, which is why they give a small range of answers rather than one exact number.
Why the Formulas Disagree Slightly
Because each was derived from different clinical datasets and assumptions, they don't converge on identical numbers â seeing a range across all four is normal and expected, not a sign anything's wrong with the calculation.
How to Actually Use These Numbers
Treat the result as a general reference point, not a strict target â useful for a rough sense of a "typical" healthy weight range for your height, but not a substitute for a broader assessment that includes body composition, muscle mass, and how you actually feel and perform.
Try the free tool
Use our free Ideal Weight Calculator â four formulas at once
Open Ideal Weight Calculator →