Ideal Weight Calculator
See the healthy weight range for your height, plus the results of the four best-known ideal body weight formulas side by side.
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“How much should I weigh?” has no single right answer, but there are good reference points. This calculator shows the healthy weight range for your height based on BMI, alongside four ideal body weight formulas that doctors and dietitians have used for decades.
How to use the ideal weight calculator
- Choose metric or US units.
- Select your sex.
- Enter your height.
The results show the healthy BMI weight range and the Devine, Robinson, Miller and Hamwi estimates.
The formulas
Each classic formula starts with a base weight at 5 feet (60 inches) and adds a fixed amount for every inch above that.
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg per inch over 5 ft | 45.5 kg + 2.3 kg per inch |
| Robinson (1983) | 52 kg + 1.9 kg per inch | 49 kg + 1.7 kg per inch |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
| Hamwi (1964) | 48 kg + 2.7 kg per inch | 45.5 kg + 2.2 kg per inch |
The healthy BMI range comes from rearranging the BMI formula:
Weight = BMI × Height(m)²
Healthy range = 18.5 × Height² to 24.9 × Height²Worked example
A man who is 5 ft 10 in (177.8 cm) tall is 10 inches over 5 feet.
- Devine: 50 + 2.3 × 10 = 73 kg (161 lb)
- Robinson: 52 + 1.9 × 10 = 71 kg (157 lb)
- Miller: 56.2 + 1.41 × 10 = 70.3 kg (155 lb)
- Hamwi: 48 + 2.7 × 10 = 75 kg (165 lb)
- Healthy BMI range: 18.5 × 1.778² to 24.9 × 1.778² = 58.5–78.7 kg (129–174 lb)
The four formulas all fall between 70 and 75 kg, comfortably inside the BMI range.
For a woman who is 5 ft 5 in (165.1 cm), the formulas give 56.5–59.9 kg and the healthy BMI range is 50.4–67.9 kg.
Where these formulas came from
- Hamwi was published in 1964 as a quick rule of thumb for diabetes diet planning.
- Devine was created in 1974 to help calculate medication doses, and it is still used in hospitals for that purpose.
- Robinson and Miller were published in 1983 as refinements based on population height and weight data.
None were designed as personal weight-loss targets, which is why the BMI range is a more practical guide for most people.
Using the results sensibly
- Think in ranges, not single numbers. Anywhere in the healthy BMI range is reasonable for most adults.
- Consider your build. People with a large frame or a lot of muscle are often healthy above the formula results.
- Waist size matters. A waist below half your height is a simple sign of a healthy weight distribution.
- Focus on habits. Sleep, activity and diet quality have a bigger effect on health than hitting an exact number on the scale.
This calculator is for general information and is not medical advice. Your doctor can help you set a target that fits your health and history.
Frequently asked questions
Which ideal weight formula is the best?
None is perfect. The healthy BMI range is the most widely used guide today. The Devine formula is still common in medicine, mainly for calculating drug doses. The four formulas usually agree within about 5 kg, which is a fair sense of how precise any single number can be.
Why do the formulas give different results?
They were built from different data sets and for different purposes, from insurance tables to drug dosing. None of them consider muscle mass, frame size or age, so treat them as rough reference points.
Does ideal weight depend on age?
These formulas ignore age. Some research suggests that slightly higher weights carry little or no extra risk in older adults, so talk to a doctor about what is right for you.
I am very muscular. Do these numbers apply to me?
Probably not well. Muscle is dense, so athletes often weigh more than any formula suggests while having low body fat. A body fat estimate or waist measurement is a better guide in that case.
Why is there a minimum height?
The classic formulas start from a height of 5 feet (152.4 cm) and add weight for each inch above it. Below about 4 ft 6 in they give unrealistic results, so the calculator asks for a taller height.