Ideal weight is a target, not a verdict
A BMI calculator tells you which category your current weight falls into. An ideal weight calculator works the other way round: it starts from your height and asks what weight is a sensible goal. You only need height and sex; add your current weight to see how far you are from that goal.
The formulas compared
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg per inch over 5 ft | 45.5 kg + 2.3 kg per inch over 5 ft |
| 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 |
| BMI 22 / 21 (Korea) | height (m)² × 22 | height (m)² × 21 |
Devine is the formula hospitals still use most for drug dosing, so it is the default here. The others were proposed as refinements, and the spread between them is a useful reminder that there is no single correct number. The inch-based formulas were built for adults at least 5 ft (152 cm) tall, so they are hidden below that height. The last row is the method Korean clinics use, handy if you live in Korea and compare notes with a local doctor.
Worked examples
Man, 5 ft 10 in (70 in): Devine gives 50 + 2.3 × 10 = 73 kg (160.9 lb). At 180 lb he is about 112% of that, which counts as overweight, and losing around 6.5 lb would bring him inside the WHO healthy range (BMI 18.5–24.9, 128.9–173.5 lb at his height).
Man, 170 cm: Devine gives about 65.9 kg, Robinson 65.2 kg, Miller 66.0 kg and the Korean BMI-22 method 63.6 kg.
Reading the result
The tool divides your current weight by the ideal weight: 90–110% is treated as normal, 110–120% as overweight and 120% or more as obese. The healthy range uses the WHO BMI band of 18.5–24.9, the same one our BMI calculator uses on the English site. If you are planning a diet, the BMR calculator estimates how many calories you burn.
Who should not rely on it
- Anyone under 18. Children and teens are assessed with growth charts by age and sex; ask a pediatrician.
- People with a lot of muscle, pregnant women, older adults and anyone managing a medical condition. Frame size and body composition matter more than a formula can show.
- Your numbers stay in your browser and are not stored or sent anywhere.