Ideal Weight Calculator

What this calculator does & how it works

This tool estimates a "healthy" body weight for your height and sex using four formulas that clinicians have used for decades. Rather than pretending there is one perfect number, it reports all four and presents the spread as a range, because your healthy weight is genuinely a band rather than a single point. Every formula here works the same way: it sets a base weight at five feet of height and adds a fixed amount for each inch above that.

The four methods are the classic ideal-body-weight formulas: the Devine formula (1974), originally created to guide medication dosing and still the most widely cited; the Robinson formula (1983) and the Miller formula (1983), which were refinements of Devine's work; and the Hamwi formula (1964), a fast clinical rule of thumb. Each uses a different base weight and per-inch increment for men and women, which is why the results differ by a few kilograms. If you enter imperial units, your height is converted to centimetres first and the final weights are converted back to pounds.

How to interpret your results

Read the range, not any single formula. If your weight already sits inside or near the band, that is reassuring. If it falls outside, that alone does not mean anything is wrong — these formulas ignore muscle, frame size, age, and body composition, so a strong, athletic build can legitimately exceed the range. The individual rows are shown mainly so you can see how much the methods disagree.

For a fuller picture, combine this with your BMI, which also factors in your actual weight, and your daily calorie needs if you are planning a change. No single tool defines a healthy weight; they are most useful together.

Limitations and when to consult a professional

These formulas are old and were derived from limited populations, mostly to standardise medication dosing rather than to define wellbeing. They depend only on height and sex, so they cannot account for body frame, muscularity, fat distribution, ethnicity, or age. They are not validated for children or adolescents, and they can mislead for very short or very tall people, pregnant people, and athletes. The "ideal" label is historical, not a judgement about your health.

If you are thinking about losing or gaining weight, have a condition that affects body composition, or feel anxious about your weight, talk to a doctor or a registered dietitian. They can interpret these numbers within your full health context and set a realistic, safe target — something a formula cannot do. Nothing here is medical advice.

A worked example: why four formulas, not one

Enter the default — a man of 170 cm — and the four classic formulas each return a slightly different "ideal" weight, all clustered in a narrow band. The Robinson formula gives about 65 kg, Devine and Miller land near 66 kg, and Hamwi comes in around 67 kg. We show all four side by side precisely because they disagree: each was derived from a different dataset in a different decade, and none has a claim to being the "true" answer. The honest reading is not any single figure but the range they span — here roughly 65 to 67 kg — which you can treat as a reasonable reference zone rather than a bullseye.

It's worth knowing where these numbers come from. Most of these equations were created not to define health but to standardize medication dosing — many drugs are dosed by body weight, and clinicians needed a consistent height-based estimate. The word "ideal" is a historical label, not a verdict on how you should look or feel. A healthy weight for a real person also depends on muscle, frame size, and body composition, none of which a height-and-sex formula can see.

How this compares to BMI, and which to trust

Ideal-weight formulas and BMI approach the same question from opposite directions. BMI takes your actual weight and height and returns a category; these formulas take only your height and return a target weight. They usually roughly agree — the formula outputs typically fall inside the normal BMI range for a given height — but when they diverge, neither is more "correct," because both share the same blind spot: they can't distinguish muscle from fat. A muscular athlete will exceed every ideal-weight formula and still be perfectly healthy. Cross-check your result against the BMI calculator for the category view, and the waist-to-height ratio for the fat-distribution view the weight formulas miss entirely.

Using a target weight sensibly

If you do adopt a number from the range as a goal, the next step is a realistic path to it. The calorie/TDEE calculator converts the gap between your current and target weight into a daily calorie plan, and a gradual approach — a few hundred calories a day — is both safer and more durable than an aggressive one. Above all, treat the "ideal" as a loose reference, not a rule to enforce; the trend of your health and how you function matter far more than hitting a specific figure a formula printed. These are educational estimates, and a professional can set a target that fits your body.

Frequently asked questions