How to use
Enter your weight and height to see your body mass index (BMI), your weight category according to the World Health Organization and the healthy weight range for your height. Height can be entered in inches or as feet and inches, e.g. 5'9".
Formula
BMI = weight (kg) / height (m)², or in US units BMI = 703 × weight (lb) / height (in)².
For example, 160 lb at 5’9” (69 in): 703 × 160 / 69² ≈ 23.6 — a healthy weight. For a height of 5’9”, the healthy range is about 125 to 169 lb.
WHO categories for adults
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5–24.9 | Healthy weight |
| 25–29.9 | Overweight |
| 30–34.9 | Obesity class I |
| 35–39.9 | Obesity class II |
| 40 and above | Obesity class III |
FAQ
Is BMI valid for children and teens? No. For children and teens, BMI is compared with age- and sex-specific percentile charts — ask a pediatrician.
Why can athletes come out as “overweight”? BMI doesn’t tell muscle from fat, so people with a lot of muscle get a higher number.
Can I use this calculator during pregnancy? Its adult weight categories are not intended to assess your current weight during pregnancy. Healthcare professionals may use your pre-pregnancy BMI when planning care.
BMI is a screening measure, not a diagnosis. Talk to a doctor about your weight and health. To estimate how many calories you need a day, try the calorie calculator.