Compare your ideal body weight across five validated clinical formulas — Robinson, Miller, Devine, Hamwi, and the BMI range. Enter your height and sex; results update live.
Results update live as you type.
Estimated ideal weight
Robinson
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Miller
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Devine
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Hamwi
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| Formula | Year | Ideal weight | Notes |
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The Formulas
Each formula starts with a baseline weight at 5 feet tall, then adds a fixed number of kilograms per inch above 5 feet. Devine, Robinson, Miller, and Hamwi use different constants — derived from different populations and decades — so they give slightly different results.
The BMI range approach is the modern alternative: a healthy BMI is 18.5–24.9, so ideal weight = BMI × height² (m). It gives a range rather than a single number.
Ideal-Weight Equations
About This Tool
An ideal weight calculator estimates a target body weight from height and sex using formulas first developed for clinical drug dosing. The most-cited are the Devine, Robinson, Miller, and Hamwi equations — all built decades apart from different population samples.
Because each formula uses different assumptions, the results vary slightly. We show all four side-by-side plus the modern BMI-range approach (18.5–24.9 × height²) so you can see the spread instead of fixating on a single number.
Worth knowing: these formulas don't account for muscle mass, bone density, or body composition. A muscular athlete and a sedentary office worker at the same height get the same "ideal" number — but their actual healthy weights differ significantly. Use this as a reference, not a target.
Instant Live Results
All five formulas update the moment you change a value.
Five Formulas
Robinson, Miller, Devine, Hamwi, plus the BMI range.
Clinical Grade
Same equations used for medication dosing in hospitals.
100% Free & Private
No account needed. All maths runs in your browser.
Sex-Specific
Different equations for men and women — more accurate for both.
Imperial & Metric
Switch between ft/lbs and cm/kg instantly.
Two inputs unlock five clinical reference numbers.
Choose Imperial (ft/in, lbs) or Metric (cm, kg). Both display the same numbers underneath.
Each formula has separate constants for males and females — pick the one that matches your biology.
Stand barefoot for the most accurate measurement. Height is the only physical input these formulas use.
Read the four numbers — they'll usually fall within ~10 lbs of each other. The big number is the average.
The BMI-range tab shows a healthy spread (BMI 18.5–24.9) — more realistic than a single number.
These don't account for muscle, frame size, or composition. Use them alongside body-fat %, BMI, and how you feel.
Everything you need to know about ideal weight formulas.
There's no single best formula. The BMI range (18.5–24.9) is most common today. Devine and Robinson are widely used in clinical settings for drug dosing. Use the average across formulas as a sensible guideline.
Not exactly. These formulas were built for clinical use, not health. They don't account for muscle mass, bone density, ethnicity, or body composition. Use them as a starting reference and combine with body-fat percentage and how you feel.
Average body composition differs by sex — men carry more muscle and less essential body fat. The formulas use different base values and per-inch coefficients to reflect that difference at the population level.
Ideal-weight formulas will flag muscular athletes as "overweight" even when they're lean. For athletes, body fat percentage and lean body mass are far more useful metrics than ideal-weight tables.
Each was developed from a different population at a different time. Hamwi (1964) sampled mostly American adults. Devine (1974) was created specifically for medication dosing. Robinson and Miller (1983) refined the numbers using newer data. The spread is normal and informative.
No — these are reference weights, not minimums or targets. Aiming below the lowest number can be harmful. A healthy weight is one you can sustain comfortably, with good energy, decent body composition, and stable labs.