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FitCalcs

Ideal Weight Calculator

See how much you should weigh for your height and sex. This calculator shows four classic ideal-weight formulas alongside your healthy BMI weight range.

Built and reviewed by Jesse · Last reviewed

Enter your height and sex to see your ideal weight estimates.

  1. Enter your height and sex. The classic formulas use height and sex to give a reference weight.
  2. Read the four estimates. Robinson, Miller, Devine, and Hamwi each give a slightly different target.
  3. Compare with your healthy BMI range. The calculator also shows the weight range for a BMI of 18.5-24.9 at your height.

Each classic formula defines a base weight at a height of 5 feet (152.4 cm) and adds a set amount for every inch above that. The four equations — Robinson, Miller, Devine, and Hamwi — differ in those numbers because each was derived from different data, which is why they produce a spread of results rather than a single figure.

Alongside the formulas, this calculator shows the weight range that corresponds to a healthy Body Mass Index (18.5–24.9) at your height. Most clinicians now favour this range over a single "ideal" number because it acknowledges that healthy bodies come in different shapes and sizes.

  1. Choose metric or imperial units and select your sex.
  2. Enter your height.
  3. Compare the four formula estimates, their average, and the healthy BMI range.
  4. Use the range — not a single number — to set a realistic goal, then head to the body weight planner to turn that target into a daily calorie number and a timeline, or the calorie deficit calculator to compare different deficit sizes.
  • Ignores body composition.The formulas use only height and sex, so a muscular person can read as "overweight" despite being lean. Check your BMI and, ideally, body fat percentage for a fuller picture.
  • No frame-size adjustment. People with larger or smaller frames naturally carry more or less weight at the same height.
  • Derived from older population data. These equations date from the 1960s–1980s and were built for clinical estimates, not as fitness goals.

Ideal body weight formulas (base at 152.4 cm / 5 ft, per inch above)

Robinson (1983): men 52 + 1.9/in;  women 49 + 1.7/in
Miller (1983):   men 56.2 + 1.41/in; women 53.1 + 1.36/in
Devine (1974):   men 50 + 2.3/in;  women 45.5 + 2.3/in
Hamwi (1964):    men 48 + 2.7/in;  women 45.5 + 2.2/in
in
= inches of height above 5 feet (152.4 cm)

Results are in kilograms. These formulas predate BMI and give a single reference weight, so the healthy BMI range is usually the more practical target.

What is ideal body weight?

Ideal body weight (IBW) is an estimate of a healthy reference weight based on your height and sex. The classic formulas were originally developed in medicine — for example, to calculate drug dosages — and give a single target number. They're a useful starting point but not a precise health goal.

Which ideal weight formula is best?

There's no single 'best' formula — the Robinson, Miller, Devine, and Hamwi equations all give slightly different numbers because they were derived from different data. That's why this calculator shows all four plus their average. For most people, the healthy BMI range is a more meaningful target than any single formula.

Why show a healthy weight range instead of one number?

Because no single weight is right for everyone of a given height. A range based on a normal BMI (18.5–24.9) reflects that healthy people come in different builds. Where you fall within that range depends on your muscle mass, frame size, and personal goals.

Do these formulas account for muscle or body fat?

No. Ideal weight formulas use only height and sex, so they can't tell muscle from fat. A muscular athlete may weigh well above their 'ideal' number while carrying very little fat. If you're lean and strong, don't be alarmed by a high reading — body fat percentage is far more informative.

Should I aim for exactly my ideal weight?

Not necessarily. Use the number as a rough reference, not a strict target. Health depends on far more than weight — activity, diet quality, sleep, strength, and metabolic markers all matter. Aim for a weight where you feel strong, energetic, and can sustain your habits long term.

Does ideal weight change with age?

The formulas themselves don't adjust for age, but a slightly higher body weight in older adults is often associated with better outcomes. As always, the formulas are a starting point — individual circumstances matter more than a single equation.

How is this different from a BMI calculator?

A BMI calculator tells you which weight category you currently fall into. An ideal weight calculator works in reverse: it estimates what you might weigh at a healthy point for your height. They're complementary — use BMI to assess where you are, and ideal weight to set a rough goal.

References

FitCalcs calculators provide general estimates for healthy adults and are not medical advice.

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