BMI Calculator
Enter your height and weight to see your body mass index, your WHO category and the healthy weight range for your height. For adults 18 and over.
| WHO category | |
| Healthy weight for your height (BMI 18.5–24.9) | |
| To reach a healthy BMI |
BMI categories for adults (WHO)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25 – 29.9 | Overweight |
| 30 – 34.9 | Obese (Class I) |
| 35 – 39.9 | Obese (Class II) |
| 40 and above | Obese (Class III) |
How it works
The calculator divides your weight by the square of your height, then places the result on the WHO adult scale. The healthy weight range is simply the weights that give a BMI between 18.5 and 24.9 at your height. If you want to turn a weight goal into a daily eating plan, try the calorie calculator next.
This is a screening tool, not medical advice. Talk to a doctor before making big changes to your weight.
Frequently asked questions
How is BMI calculated?
BMI is your weight in kilograms divided by your height in meters squared. For someone 175 cm tall weighing 70 kg, that is 70 / (1.75 x 1.75) = 22.9. In US units the formula is 703 x weight (lb) / height (in) squared, which gives the same result.
What is a healthy BMI for adults?
The World Health Organization classes a BMI under 18.5 as underweight, 18.5 to 24.9 as normal weight, 25 to 29.9 as overweight and 30 or more as obese. Some Asian health bodies use lower cut-offs (overweight from 23) because health risks rise at a lower BMI in Asian populations.
Is a normal BMI the same as being healthy?
Not always. BMI only looks at height and weight, so it cannot tell muscle from fat or show where fat is stored. Muscular people can score high, and people with little muscle can score normal while carrying a lot of body fat. Waist size (for example over 40 in / 102 cm for men or 35 in / 88 cm for women) adds useful context.
Can I use this for children or teens?
No. For anyone under 18, BMI is judged against age- and sex-specific growth charts (BMI-for-age percentiles), not the adult categories used here. Ask a pediatrician or use a dedicated child BMI chart.