⚖️Ideal Weight Calculator
Enter your height to see what Devine, Robinson, Miller, Hamwi, and the BMI healthy range each suggest — displayed as a range of reference estimates, not a single target.
This tool is a general reference and is not medical or dietary advice. "Ideal weight" is not a fixed target — formula estimates vary, and none accounts for body composition, muscle mass, frame size, age, or individual differences. Please consult a registered dietitian or physician before making any decisions about your weight or health. If you find yourself preoccupied with your weight or body, consider reaching out to a qualified professional for support.
Free Ideal Weight Calculator Online
Curious what the well-known "ideal weight" formulas say for your height? Our free Ideal Weight Calculator shows them side by side. Rather than handing you one number, it presents a range of reference estimates — from the classic Devine, Robinson, Miller, and Hamwi formulas — alongside the healthy-weight range based on BMI for your height, so you can see how much they differ.
And they do differ, which is the point. Most of these formulas are decades old and several were originally created for medication dosing, not as health goals. None account for muscle, body composition, frame size, or individual differences. "Ideal weight" is really a misnomer — there's a healthy range, not a single correct number. This tool is a factual reference for understanding what those formulas produce and why to read them with healthy scepticism.
Simply enter your height to see the range instantly. No sign-up, no downloads, no limits. For anything about your own weight or health, please speak with a doctor or dietitian.
About the Ideal Weight Calculator
Key features
Four classic formulas side by side
Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964) are computed simultaneously for your height and sex, each shown in its own card with a brief note on its origin so you understand the context behind the number.
BMI healthy weight range
Alongside the formula estimates, the tool shows the low end (BMI 18.5) and high end (BMI 24.9) of the standard healthy weight range for your height — a fifth reference that doesn't require a sex input.
Overall spread indicator
A summary row shows the full spread from the lowest to the highest value across all methods, making the disagreement between formulas immediately visible rather than buried in individual cards.
Metric and imperial
Enter height in centimetres or feet and inches; choose output in kg or lb. The tool converts automatically and all formulas produce the same results regardless of which unit system you choose.
The formulas
Devine (1974)
Male: 50 + 2.3 × (inches above 60). Female: 45.5 + 2.3 × (inches above 60). Originally designed to estimate drug dosing weights in clinical pharmacology, not as a personal health target.
Robinson (1983)
Male: 52 + 1.9 × (inches above 60). Female: 49 + 1.7 × (inches above 60). A modification of the Devine formula with slightly different coefficients derived from a re-analysis of population data.
Miller (1983)
Male: 56.2 + 1.41 × (inches above 60). Female: 53.1 + 1.36 × (inches above 60). Tends to produce somewhat higher estimates than Devine and Robinson; developed from a different population sample.
Hamwi (1964)
Male: 48 + 2.7 × (inches above 60). Female: 45 + 2.2 × (inches above 60). One of the oldest clinical rules of thumb, originally described for use in nutritional assessment of diabetic patients.
All four formulas are defined for heights above 5 ft / 152 cm (60 inches). For shorter heights they produce implausible or negative values, so the tool notes this rather than displaying a meaningless result.
Why these formulas have real limits
No body composition
A 175 cm athlete with 10% body fat and a 175 cm sedentary person with 35% body fat receive identical formula results. Muscle and fat are invisible to these equations.
No frame or build
Frame size — small, medium, large — is not accounted for. Two people of the same height but meaningfully different bone structure will naturally carry different healthy weights.
No age factor
Healthy body composition shifts with age. These formulas produce the same output regardless of whether you are 25 or 75, which limits their clinical relevance outside a narrow demographic.
Formulas disagree
For a 5'10" male the four formulas produce a spread of several kilograms. This disagreement itself tells you something important: there is no single "correct" answer hidden in one of them.
Frequently Asked Questions
How does the Ideal Weight Calculator work?
Enter your height and sex, and the tool computes what each of the four classic formulas (Devine, Robinson, Miller, Hamwi) produces for those inputs, alongside the healthy-weight range from BMI (18.5–24.9) for your height. All five results are shown side by side so you can see how much they differ — no single number is presented as a target.
Why does it show several numbers instead of one?
Because the formulas disagree — sometimes by several kilograms — and none is definitive. Showing the spread is more honest than implying one correct answer. The range across methods gives a better sense of the genuine uncertainty in these estimates.
Which formulas are used?
The tool uses four classic ideal body weight formulas: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). It also shows the BMI healthy-weight range (18.5–24.9 × height²) as a fifth reference point. Each formula card shows a brief note on its origin and context.
Is "ideal weight" a real medical target?
Not really. Most of these formulas are decades old and several — including Devine and Hamwi — were originally developed for medication dosing calculations, not as personal health targets. Health is far better understood as a range across many factors, not a single number on a scale.
Why don't the formulas account for muscle or body build?
They are simple linear equations based only on height. They cannot distinguish muscle from fat, account for frame size, bone density, age, or individual variation. This is one of their core limitations — a heavily muscled person and a sedentary person of the same height get the same formula result.
Does it work in metric and imperial?
Yes. You can enter your height in centimetres or in feet and inches, and choose whether to see results in kg or lb. The formulas produce identical results regardless of which unit system you use — the tool handles the conversion automatically.
Which number should I use as my goal?
Please don't treat any of these as a target. Use the range as general context only. For anything about your personal weight or health, rely on a registered dietitian or physician rather than any formula — they can account for the factors these equations ignore.
Is my data stored anywhere?
No. Your height and sex are processed entirely in your browser and are never stored or sent to any server, keeping your information completely private.
Does it work on mobile?
Yes. The tool is fully responsive — the comparison panel stacks vertically on small screens so nothing overflows and all results remain easy to read on any device without horizontal scrolling.
Should I try to reach one of these numbers?
Please don't treat any formula result as a target to aim for. These are historical reference estimates, not medical or dietary prescriptions. For personal guidance about your weight or health, consult a doctor or registered dietitian. If you find yourself preoccupied with your weight or body, consider reaching out to a qualified professional for support.