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Ideal Weight Calculator

See your ideal body weight for your height and sex using the Robinson, Miller, Devine and Hamwi formulas, next to the healthy BMI range.

Formulas last reviewed: September 2026

Disclaimer: Results are general estimates for information and education only. They are not medical advice, a diagnosis or a treatment plan. Please talk to a doctor or qualified health professional before making health, diet, exercise or pregnancy decisions.

What is ideal body weight?

Ideal body weight (IBW) is an estimate of a healthy weight for your height and sex. Doctors have used these formulas since the 1960s, often to work out medicine doses.

There is no single perfect number, so the calculator shows four classic formulas alongside the healthy BMI range for your height.

How it is calculated

Devine: 50 kg (men) / 45.5 kg (women) + 2.3 kg per inch over 5 feet
Robinson, Miller and Hamwi use similar formulas with different constants

Worked example

Man, 5 ft 9 in (175 cm)

Robinson
69.1 kg
Miller
68.9 kg
Devine
70.7 kg
Hamwi
72.3 kg

The four formulas differ by a few kilograms, which is normal.

Use ideal weight wisely

  • Formulas ignore muscle, bone size and age, so treat the result as a range, not a target.
  • For Indians, the healthy BMI range (18.5 to 22.9 on Asian cut-offs) is often more useful.
  • Waist size and fitness matter as much as the number on the scale.

Frequently asked questions

Which ideal weight formula is best?

None is perfect. Devine is the most widely used in medicine. Looking at the range across all four formulas is more useful than picking one.

Is ideal weight the same as healthy weight?

Not exactly. Healthy weight is usually a range based on BMI, while ideal weight formulas give a single estimate for your height and sex.

Does age change ideal weight?

These formulas do not use age, but body composition changes with age. Older adults may be healthier at the upper end of the range.

What if the formulas give different numbers?

That is expected because they came from different studies. Use the overlap and your doctor's advice rather than a single figure.