Ideal Weight Calculator
Compare the four classic ideal body weight formulas against the healthy BMI range for your height.
Your details
These formulas were derived separately for each sex and are not interchangeable.
This calculator runs entirely on your device. Nothing you enter is uploaded, stored, or sold. How this works
Ideal body weight
159.4 lb
average of four formulas · healthy BMI range 128.9 lb to 173.5 lb
Includes your inputs, the full breakdown, and every row of the table.
Your current BMI
25.8
Healthy range low
128.9 lb
Healthy range high
173.5 lb
Above the formula average
20.6 lb
- Devine (1974)
- 160.9 lb
- Robinson (1983)
- 156.5 lb
- Miller (1983)
- 155.0 lb
- Hamwi (1964)
- 165.3 lb
- Average
- 159.4 lb
- BMI-based healthy range
- 128.9 lb – 173.5 lb
What this means
- At 180.0 lb you sit above the healthy BMI band of 128.9 lb to 173.5 lb.
- Every formula here was built for clinical drug dosing, not for aesthetics or athletic performance. None of them account for muscle mass, frame size or body composition.
How the ideal weight calculation works
Ideal body weight formulas were not invented to tell people what to weigh. Devine published his in 1974 as a way to calculate gentamicin doses, and the others that followed were refinements aimed at the same clinical problem — you need a stable reference weight to scale a drug against, and actual body weight distorts that badly in obese patients. They ended up in the popular imagination as targets, which was never their purpose.
That history explains their most obvious weakness: they depend on height and sex alone. Two people of identical height get an identical number regardless of frame, musculature or age. A heavily trained athlete will be told they are overweight by every formula on this page, and a sedentary person with very little muscle may hit the target while carrying an unhealthy amount of fat.
The healthy BMI range shown alongside them is a better everyday benchmark because it is a range rather than a point, which honestly reflects that there is no single correct weight for a given height. Even so, BMI shares the same blindness to body composition. If you want a number that reflects your actual health, waist circumference and body fat percentage tell you considerably more than either.
Frequently asked questions
Why do the four formulas give different answers?
They were fitted to different populations at different times, and each makes its own assumption about how weight should scale with height. Hamwi is the oldest and most generous at taller heights; Miller rises most slowly. The spread between them is a fair indication of how imprecise the whole concept is.
Should I actually try to reach my ideal body weight?
Not as a target in itself. These formulas ignore muscle, frame and age entirely, so the number may be unrealistic in either direction. Sitting anywhere within the healthy BMI range while maintaining decent fitness and a reasonable waist measurement is a more sensible goal.
Does this work for athletes?
Poorly. Muscle is denser than fat, so anyone with substantial lean mass will read as overweight on both the formulas and BMI. Body fat percentage is the appropriate measure for athletic populations, and this calculator will consistently understate a healthy weight for them.
Do these formulas apply to children?
No. All four assume an adult skeleton and start from a fixed base weight at five feet, which makes them meaningless for anyone still growing. Paediatric assessment uses age-and-sex growth percentiles instead.
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Disclaimer. This calculator is provided for general information and educational purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Results are estimates based on the inputs you provide and the assumptions described above. Confirm any figure with a qualified professional before acting on it.