Ideal Body Weight Calculator

Ideal Body Weight Calculator

Compare several historical height-based body-weight formulas for adults.

Please enter a valid height of at least 5 feet (152.4 cm).
Average of 4 formulas
--
kg reference estimate
--Devine formula
--Robinson formula
--Miller formula
--Hamwi formula
Healthy-BMI comparison range (18.5–24.9): --
“Ideal body weight” is a historical formula concept, not a single medically perfect weight. Different formulas can give different results and do not directly account for body composition or individual health.
IBW Guide

What Does “Ideal Body Weight” Mean?

Ideal body weight, often shortened to IBW, is a historical term used for formulas that estimate a reference body weight mainly from height and sex. These equations were developed for different purposes and at different times, so they do not all produce the same answer.

This calculator therefore shows several established formulas side by side instead of presenting one number as a medically perfect target. The average is displayed only as a convenient comparison of the four results.

Health information notice: A formula-based reference weight is not a diagnosis or a personalized treatment goal. Body composition, age, health conditions, pregnancy, medications, genetics, and other factors can matter when evaluating weight and health.
1

Choose Metric or Imperial

Enter height in centimetres or in feet and inches. The historical formulas used here are generally applied to heights of at least 5 feet.

2

Compare Multiple Formulas

The calculator returns Devine, Robinson, Miller, and Hamwi estimates so you can see how much historical formulas may differ.

Formulas

Which Ideal Body Weight Formulas Are Used?

Devine: Men = 50 kg + 2.3 kg per inch over 5 ft; Women = 45.5 kg + 2.3 kg per inch over 5 ft.
Robinson: Men = 52 kg + 1.9 kg per inch over 5 ft; Women = 49 kg + 1.7 kg per inch over 5 ft.
Miller: Men = 56.2 kg + 1.41 kg per inch over 5 ft; Women = 53.1 kg + 1.36 kg per inch over 5 ft.
Hamwi: Men = 106 lb + 6 lb per inch over 5 ft; Women = 100 lb + 5 lb per inch over 5 ft.

The formulas were developed from different historical approaches, including height-weight tables and drug-dosing applications. Because their methods differ, variation between results is expected.

Comparison

Why Does the Calculator Show More Than One Result?

Research comparing common IBW formulas has shown that they can produce meaningfully different estimates at the same height. That is one reason a single “ideal” number should not be treated as universally correct.

FormulaMain inputImportant context
DevineHeight + sexHistorically associated with drug-dosing calculations.
RobinsonHeight + sexDerived from Metropolitan Life height-weight data.
MillerHeight + sexAnother regression-based height-weight formula.
HamwiHeight + sexOlder clinical rule using pounds and inches.
BMI Comparison

Why Is a Healthy-BMI Weight Range Also Shown?

The calculator also displays the body-weight range that corresponds to an adult BMI of 18.5 to 24.9 for the entered height. This is provided as a separate comparison, not as proof that every weight in the range is ideal for every person.

BMI itself is a screening measure and does not directly measure body fat, muscle mass, fitness, or overall health. The BMI comparison should therefore be interpreted with the same caution as other simple weight formulas.

Limitations

What These Formulas Do Not Consider

Traditional ideal-body-weight equations are simple. They do not directly include muscle mass, body-fat percentage, waist circumference, bone structure, ethnicity, fitness level, medical history, or many other factors that may matter to an individual's health.

A person who is very muscular may naturally weigh more than a formula estimate. Another person may fall close to a formula estimate while still having health concerns unrelated to body weight. For these reasons, the result is best viewed as a historical reference calculation rather than a personal medical target.

Who Should Be Careful

When an Online IBW Calculator May Not Be Appropriate

This tool is intended for general adult educational use. It is not designed to set weight goals for children or teenagers, pregnancy, breastfeeding, people with an eating disorder, or people whose medical care requires a specific weight calculation.

Some clinical uses—such as medication dosing or ventilation settings—may require a particular formula or a different concept such as predicted body weight. Follow the method specified by the treating healthcare professional rather than substituting an online calculator.

Frequently Asked Questions

Ideal Body Weight Calculator FAQs

Is there one scientifically perfect ideal body weight?

No. Different historical formulas can produce different reference weights, and none captures every factor that affects an individual's health or body composition.

Why are there separate male and female formulas?

The historical formulas were developed with sex-specific constants. The calculator follows those published formula structures rather than claiming that sex alone determines a healthy personal weight.

Can I use this calculator if I am shorter than 5 feet?

Many classic IBW formulas are expressed for height at or above 5 feet. This calculator therefore requires at least 5 feet (152.4 cm) to avoid extending the formulas beyond their usual presentation.

Should I try to reach the average number shown?

Not necessarily. The average is only a comparison of four formulas, not a personalized medical recommendation or treatment target.

Can this calculator be used during pregnancy?

No. Pregnancy involves expected weight changes and specific nutritional needs. Personalized prenatal guidance is more appropriate.

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