Ideal Weight Calculator
| Formula | Year | Result |
|---|
How This Calculator Works
Four classic formulas, each using "inches above 5 feet" as the height variable. The calculator averages them.
Let i = (height in inches) − 60.
Devine 1974 Men: 50.0 + 2.3 × i Women: 45.5 + 2.3 × i
Robinson 1983 Men: 52.0 + 1.9 × i Women: 49.0 + 1.7 × i
Miller 1983 Men: 56.2 + 1.41 × i Women: 53.1 + 1.36 × i
Hamwi 1964 Men: 48.0 + 2.7 × i Women: 45.5 + 2.2 × i
(All return weight in kilograms.)Citations: Devine BJ, "Gentamicin therapy," Drug Intelligence and Clinical Pharmacy, 1974;8:650–655. Robinson JD, et al., "Determination of ideal body weight for drug dosage calculations," American Journal of Hospital Pharmacy, 1983;40(6):1016–1019. Miller DR, et al., "Predicting the dose of vancomycin," DICP, 1989;23(2):169–171 (using earlier Miller formula). Hamwi GJ, "Therapy: changing dietary concepts," in Danowski TS (ed.), Diabetes Mellitus: Diagnosis and Treatment, Vol. 1, American Diabetes Association, 1964:73–78.
What This Means
These formulas were originally derived for hospital and pharmaceutical use — calculating medication doses, planning clinical nutrition. Treat the result as a reference, not a target. A muscular athlete will weigh well above this; a small-framed sedentary person might be best below it. Your healthy weight depends on what your weight is made of, not just height.
Limitations
Linear formulas break down at the extremes — very tall (over 6'4") or very short (under 5'0") people get weird results. None of them account for frame size, muscle mass, or body composition. The four-formula average is a useful smoothing trick but doesn't fix the underlying limitation: a single number from height alone can't capture what a healthy weight means for an individual.
Frequently Asked Questions
What is 'ideal' body weight?
It's an estimate, not a target carved in stone. The four classic formulas — Devine, Robinson, Miller, and Hamwi — were developed mostly for medical contexts (drug dosing, hospital nutrition planning), not as personal goal weights. They give you a population-average reference point. Real 'ideal' depends on body composition, activity, and goals, not just height.
Why are there four formulas?
Because researchers kept refining the original. Hamwi (1964) was first, derived from insurance company life-expectancy tables. Devine (1974) revised it for medication dosing in hospitals. Robinson (1983) re-derived the formula from population data. Miller (1983) tweaked it again. They give similar but slightly different answers, so this calculator averages all four for a less arbitrary reference.
Should I aim for my 'ideal weight'?
Maybe — but only as a rough reference. If you carry significant muscle, your healthy weight is well above these numbers. If you're sedentary with high body fat percentage, you might benefit from being below. Body composition matters more than a number on a scale. Use these formulas as a sanity check, not a finish line.
Why are the formulas different for men and women?
Because at a given height, men carry more lean muscle on average than women. The original formulas were derived from population samples that already had a sex difference in body composition. The math just bakes that difference in.
Do these work for very tall or very short people?
Less well at the extremes. The formulas were derived from population samples that didn't include many people much over 6'4" or much under 5'0". Devine and friends use a linear model that breaks down at the tails. If you're at the extremes, take the answer with a bigger grain of salt.
What about frame size?
These formulas don't account for it. Older insurance company tables used to add small/medium/large frame adjustments (±10%), but modern formulas dropped that because frame size is hard to measure consistently. You can mentally add 10% if you have a notably broad frame, subtract 10% if very narrow.
Are these still used in medicine?
Yes. The Devine formula in particular is still used for calculating loading doses of certain medications (especially in hospitals and ICUs) where body composition matters more than total weight. That's actually where most of these formulas live their day-to-day life.
What's a more useful number than ideal weight?
Body fat percentage tells you what your weight is made of. Waist circumference predicts cardiovascular risk better than weight alone. Strength and cardiovascular fitness markers (e.g., VO2 max, deadlift relative to bodyweight) tell you about capacity. Ideal weight is a reasonable starting reference; these tell you whether the weight you're at is the right composition.