Ideal Weight Calculator
Ideal body weight by the four formulas medicine actually cites — Devine, Robinson, Miller, Hamwi — side by side, plus the healthy-BMI band for your height. Four numbers rather than one, because 'ideal' is an estimate and honest tools show the spread.
Where these formulas come from
Ideal body weight was never a beauty metric — it is a dosing variable. Devine proposed his line in 1974 so that drug doses could scale with lean body size rather than total weight, and hydrophilic drugs are dosed on it to this day. Robinson and Miller are later refits of the same idea; Hamwi predates them all as a clinician's mental shortcut.
All four share one anchor — a base weight at five feet, a slope per inch above — which is why they agree near average heights and fan out at the extremes. The BMI band under them is the modern epidemiological answer: not one weight, but the range in which population health risk is flat.
Frequently asked questions
Why four different answers?
Because each author fit a line through different clinical data: Devine (1974) wrote the dosing convention, Robinson and Miller refit it in 1983 with gentler slopes, Hamwi (1964) was a bedside rule. The spread between them — often 3 to 6 kg — is the honest uncertainty of the concept itself.
Which number should I actually use?
For drug-dose questions, Devine — that is what pharmacology references mean by IBW. For a personal target, the BMI band is more defensible than any single point: anywhere inside 18.5–24.9 is medically unremarkable, and the band width shows how much room 'healthy' genuinely has.
Why does it refuse heights under 152 cm?
Every one of these formulas is a straight line anchored at 5 feet, extrapolating downward from data that contained almost nobody shorter. Below the anchor they drift into nonsense — Devine hands a 140 cm woman about 34 kg. Refusing is more useful than a confident wrong number.
Do these formulas apply to athletes or older people?
Poorly. They know only height and sex — not muscle, frame or age. A muscular person exceeds every formula while carrying little fat; muscle mass in older age shifts what a healthy weight is. Treat the numbers as population reference points, not personal verdicts.
Related tools
- BMI CalculatorBody mass index on the WHO adult scale, metric or imperial, with the normal-range weight for your height and the scale's limits stated plainly.
- Calorie Calculator (BMR & TDEE)Your basal metabolism by Mifflin–St Jeor and your daily calories by activity level, with honest ±500 kcal bands for losing or gaining.
- Running Pace CalculatorPace, finish time or distance — enter any two and get the third, with splits for 5K, 10K, half and the exact 42.195 km marathon.