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Ideal Weight Calculator

Estimate your ideal body weight using four classic clinical formulas and your healthy BMI range. Free, private and instant — every calculation runs on your device.

MB By Mustafa Bilgic · Updated 2026-06-13 · 5 min read · Fitness Tools

Ever wondered what you “should” weigh for your height? Ideal body weight (IBW) formulas were created in medicine to answer exactly that. This calculator runs four of the classic formulas — Robinson, Miller, Devine and Hamwi — averages them, and also shows the healthy weight range that corresponds to a normal BMI for your height. Treat the result as a useful reference, not a rigid target: it is based on height and sex and cannot see your muscle or build.

Calculate your ideal weight

Units

Sexformulas differ slightly by sex

Heightin centimetres

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average estimate

Healthy BMI weight range: –

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Robinson

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Miller

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Devine

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Hamwi

The four formulas, compared

Each formula starts from a base weight at five feet of height and adds a set amount per inch above that. They were derived from different data sets, so they disagree slightly — which is why showing all four (and the average) is more honest than quoting one number.

For a 180 cm man the four formulas land within a few kilograms of each other; the calculator averages them and shows your personal figures.

What ideal weight can’t tell you

These formulas have a real blind spot: they only know your height and sex. They cannot see muscle. Because muscle is denser than fat, a lean, well-trained person often weighs above their calculated ideal weight while being perfectly healthy — many athletes do. That is why this tool also shows your healthy BMI range rather than a single figure, and why we suggest pairing it with body composition.

A better picture of health

Combine your ideal-weight estimate with your BMI, your body-fat percentage and a simple waist measurement. Together these tell you far more than the scale alone. To set calorie targets for changing your weight, use the TDEE calculator.

What to do with your number

If your weight sits well within the healthy range, there is usually no need to chase a specific figure — focus on fitness and body composition. If it is well outside, the estimate can help set a sensible direction: read how to lose fat or how to build muscle depending on your goal, and remember that the aim is health, not a precise number on the scale.

Sources & further reading

External links are provided for reference and do not imply endorsement. arsenal.fit is an independent publisher and is not affiliated with any cited organisation.

Not medical advice. arsenal.fit publishes general educational fitness information. It is not a substitute for professional medical guidance. Talk to a doctor before starting a new exercise programme, especially if you are pregnant, recovering from injury or illness, or managing a health condition. Sources are cited from public health and exercise-science organisations (CDC, ACE, NSCA, ACSM, PubMed).

Frequently asked questions

What is ideal body weight?

Ideal body weight (IBW) is an estimate of a healthy weight for your height, originally devised in medicine to help dose medications and assess patients. Several formulas exist (Robinson, Miller, Devine, Hamwi), and they give slightly different numbers. They are useful reference points, not exact targets — your healthy weight also depends on build, muscle mass and body composition.

How accurate are ideal weight formulas?

They are reasonable estimates for average builds but have real limits: they are based mainly on height and sex and ignore muscle mass and frame size. A muscular athlete may sit well above their “ideal” weight while being very lean and healthy. Treat the result as a ballpark and combine it with your BMI range, body fat and waist measurement.

Which ideal weight formula is best?

No single formula is definitively best — that is why this calculator shows four and averages them. The Devine formula is the most widely used in clinical settings, while Robinson and Miller tend to give slightly lower figures. The average across them, alongside your healthy BMI range, gives the most balanced picture.

Is ideal weight the same as a healthy weight?

Not exactly. “Ideal weight” from these formulas is a single estimated figure, whereas a healthy weight is really a range — the calculator also shows the span corresponding to a BMI of 18.5–24.9 for your height. Most people are healthy anywhere within that range, so a range is more realistic than one number.

Does muscle mass affect ideal weight?

Yes, significantly — and it is the main weakness of these formulas. Muscle is denser than fat, so a lean, muscular person can weigh more than their calculated ideal weight while being very healthy. If you train seriously, lean on body-composition measures like our body-fat calculator rather than weight alone.

Should I aim for my ideal weight?

Use it as a guide, not a fixation. Health is better reflected by body composition, fitness, waist measurement and how you feel than by hitting a precise number on the scale. If your weight is well outside the healthy range, the formulas can help set a sensible direction — but the goal is health, not a specific figure.