How to use the ideal Weight Calculator
- Choose your sex.
- Choose metric or imperial units.
- Enter your height. In imperial mode, enter feet and inches separately.
- The result updates instantly as you type. There is no button to press.
- Use Copy result to copy the figures, or Copy link to share a link that reopens the ideal Weight Calculator with the same inputs.
How it works
"Ideal body weight" formulas were not designed as beauty or fitness targets. They were created by clinicians, mainly to calculate drug doses. The best known, the Devine formula from 1974, is still used in hospitals to dose certain medicines and to set ventilator settings. Later researchers, including Robinson and Miller, refined the numbers using population data, and the older Hamwi formula is still used by some dietitians.
All four formulas share the same shape: a base weight for someone 5 feet (152.4 cm) tall, plus a fixed amount for each inch above that. They differ in those two numbers, which is why they give a spread of results. None of them accounts for age, frame size or muscle, so treat the range rather than any single number as the useful answer.
The calculator also shows the weight range that corresponds to a healthy BMI of 18.5 to 24.9 for your height. That range is much wider and is the one most public-health bodies use. If your weight is anywhere within it and your waist measurement is healthy, small differences from a formula's "ideal" number are not usually a concern.
Formula
Values are shown as men / women. The healthy BMI range is 18.5 × height² to 24.9 × height², with height in metres.
Example
A man 175 cm tall is 68.9 inches, or 8.9 inches over 5 feet. Devine gives 50 + 2.3 × 8.9 ≈ 70.5 kg; Robinson 68.9 kg; Miller 68.7 kg; Hamwi 72.0 kg. The healthy BMI range at that height is about 56.7 to 76.3 kg, so all four formulas sit comfortably inside it.
Frequently asked questions
Which ideal weight formula is best?
No single formula is best for everyone. Devine is the most widely used in medicine, Robinson and Miller were fitted to later population data, and all are rough guides. The healthy BMI range is a broader and more practical target.
Why doesn't the calculator ask for my age?
These formulas only use height and sex. Weight naturally shifts with age and muscle mass, which is one reason to treat the result as a guide rather than a goal.
Does frame size matter?
Yes. Some practitioners adjust by about 10% up for a large frame and 10% down for a small frame, often judged by wrist circumference. The formulas themselves assume a medium frame.
Disclaimer: This calculator provides general estimates for education only and is not medical advice, diagnosis or treatment. Formulas are based on population averages and may not fit your body, age, pregnancy or health conditions. Talk to a doctor, midwife or registered dietitian before making decisions about your health.