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Ideal Weight Calculator

This ideal weight calculator shows what four classic formulas say about your height.

Your numbers

Sex used in the formula

These formulas come in a male and a female version. Pick the one that fits best.

These formulas start at 5 feet (152.4 cm).

Where to go next

Field Notes that go deeper

The science behind the ideal weight calculator

Show the formulas, method and sources

Ideal body weight formulas estimate a reference weight from height and sex alone. The tool runs four of them side by side, so you can see how far they disagree. Because they ignore so much, none of them works as a health target.

Formulas

Devine

  • Men: 50 kg + 2.3 kg per inch over 5 feet
  • Women: 45.5 kg + 2.3 kg per inch over 5 feet

Robinson

  • Men: 52 kg + 1.9 kg per inch over 5 feet
  • Women: 49 kg + 1.7 kg per inch over 5 feet

Miller

  • Men: 56.2 kg + 1.41 kg per inch over 5 feet
  • Women: 53.1 kg + 1.36 kg per inch over 5 feet

Hamwi

  • Men: 106 lb + 6 lb per inch over 5 feet
  • Women: 100 lb + 5 lb per inch over 5 feet

How it works, step by step

  1. First, the calculator converts your height to inches and subtracts 60 inches, which is 5 feet.
  2. Then each formula multiplies the extra inches by its own rate and adds the result to its base weight.
  3. Finally, it shows the lowest and highest of the four results as a range.

Worked example

A man who is 170 cm tall stands about 66.9 inches, so he sits 6.9 inches over 5 feet. Devine gives 50 + 2.3 x 6.9 = 65.9 kg. Robinson gives 65.2 kg, Miller 66.0 kg and Hamwi 66.9 kg.

Accuracy and limits

Pai and Paloucek traced these equations to height-weight tables, whose weights correlated with mortality. Later, because some drugs followed ideal weight, the Devine equations entered drug dosing. The equations look alike because the tables behind them agreed with each other.

Even so, the formulas differ in practice. Walter and Patel found that the gap between Devine and the other formulas reached 14% in men and 19% in women across the heights they tested.

  • The formulas also ignore age, frame size, muscle and body composition.
  • They come from height-weight tables and drug dosing, so they do not serve as personal health targets.
  • If you want a health-based view, use the healthy weight band beside your result, and talk with a clinician about your goals.

Sources

  1. Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother. 2000;34(9):1066-1069. Used for: Where the ideal body weight equations came from.
  2. Walter E, Patel A. Variability in ideal body weight formulae. J Intensive Care Soc. 2020;24(3 Suppl):16-17. Used for: Values by height for each formula and how far they differ.
  3. Centers for Disease Control and Prevention. Adult BMI categories (page dated March 19, 2024). Used for: The adult BMI cut points and the description of BMI as a screening measure.

Sources and math last reviewed: .

Questions people ask

What is ideal body weight?

It is a reference weight worked out from height and sex. Clinicians have used it for decades, for example when they dose certain drugs. Nobody designed it to describe the best weight for each person.

What is the difference between the Devine and Robinson formulas?

Both start from 5 feet and add weight for each inch. Devine adds 2.3 kg per inch for both sexes. Robinson adds 1.9 kg for men and 1.7 kg for women, so it gives lower numbers for taller people.

Why does the calculator give four answers?

Because the formulas disagree. Showing the spread is more honest than picking one, so you can judge the gap yourself. If the range is narrow at your height, the choice matters little, and if it is wide, you should treat any single number with care.

Is ideal weight the same as a healthy weight?

No. A healthy weight band based on BMI appears beside your result for comparison. It often covers a wider range than the formulas do. Because neither one accounts for muscle, use both as context and not as goals.

Why does the calculator start at 5 feet?

Each formula starts from a base weight at 5 feet and adds weight for every inch above it. At shorter heights the formulas can return weights below the healthy BMI band, so this calculator does not show them. A clinician can advise on a healthy weight at shorter heights.

These calculators give general estimates for adults and are not medical advice. For decisions about your own health, talk with a doctor or a registered dietitian. How we write and check things