Ideal Weight Calculator
Estimate a healthy target body weight from height and gender.
56.9 kg
About this calculator
What Is Ideal Body Weight?
Ideal body weight (IBW) is an estimate of the weight that is likely to be healthy for your height, based on formulas that also take sex into account. This ideal weight calculator shows the results of several well-known formulas side by side — the Robinson, Miller, Devine and Hamwi equations — plus the weight range that corresponds to a healthy BMI, so you can compare rather than rely on a single number.
Where the Formulas Come From
Ideal body weight was not invented for fashion or fitness. The first formulas, such as Devine's in 1974, were created to help doctors estimate safe drug doses. Over time people began using them as weight targets. Typical forms start from a base weight for 5 feet of height and add a fixed amount for every extra inch:
- Devine: men 50 kg + 2.3 kg per inch over 5 ft; women 45.5 kg + 2.3 kg per inch.
- Robinson: men 52 kg + 1.9 kg per inch; women 49 kg + 1.7 kg per inch.
- Miller: men 56.2 kg + 1.41 kg per inch; women 53.1 kg + 1.36 kg per inch.
- Hamwi: men 48 kg + 2.7 kg per inch; women 45.5 kg + 2.2 kg per inch.
Worked Example
A woman at 165 cm (about 65 inches) tall has an ideal weight of about 56.9 kg (125.5 lb). A man at the same height comes out higher, around 61.4 kg, since the formula uses a different baseline for men.
The Healthy BMI Range
Another way to define a healthy weight is the range where BMI falls between 18.5 and 24.9. For a person who is 1.75 m tall that spans roughly 57 to 76 kg. Because it gives a range instead of a single value, many health professionals prefer it to a point estimate. Check your BMI with the BMI Calculator.
Limits of "Ideal" Weight
Formulas ignore body composition, bone structure, age, muscle mass and ethnicity. A fit athlete can weigh well above the "ideal" and be perfectly healthy, while someone at the "ideal" weight can have a high body fat percentage. How much you should weigh is not an exact science; it depends on your health, fitness and goals. Use the result as a loose reference, and consider your body fat percentage and a doctor's advice before setting a target.
Worked example
At 165cm (about 5'5"), the Devine formula estimates an ideal weight of about 56.9 kg (125 lb) for a woman.
Frequently asked questions
Where does the Devine formula come from?
It was originally developed in 1974 for medical dosing calculations, not as a fitness target — it's still widely used as a quick reference point precisely because it's simple and well established.
Is this the same as a "healthy weight"?
Not exactly — it's one formula's estimate based purely on height and gender. Frame size, muscle mass, and overall health matter too, so treat this as a reference point rather than a strict target.
Why does the result only depend on height and gender?
That's a limitation of this particular formula — it doesn't account for age, frame size, or muscle mass, which is why different "ideal weight" formulas (Devine, Robinson, Hamwi) can give noticeably different answers for the same person.
