BMI ranges
| BMI | WHO 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 |
South Asian adults: people of South Asian background tend to develop diabetes and heart disease at lower BMIs. A World Health Organization expert group suggested extra action points for Asian populations: a BMI of 23 or more as increased risk, and 27.5 or more as high risk. The calculator shows both.
How BMI is calculated
BMI = weight in kilograms ÷ (height in metres)². For someone 1.70 m tall weighing 70 kg: 70 ÷ (1.70 × 1.70) = 24.2. In pounds and inches, BMI = 703 × pounds ÷ inches².
BMI is a quick screening number, not a diagnosis. It doesn’t tell fat from muscle, and waist size matters too. If you’re worried about your weight or health, talk to a doctor. This page is general information, not medical advice.
Frequently asked questions
What is a healthy BMI?
For adults, the WHO healthy range is 18.5 to 24.9. For South Asian adults, many doctors aim for below 23.
How do I calculate BMI in feet and pounds?
Turn your height into inches (5 feet 7 inches = 67 inches), then BMI = 703 × weight in pounds ÷ (inches × inches).
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so muscular people can have a high BMI without extra fat.
Can children use this calculator?
No. Children and teenagers need BMI-for-age charts, which compare them with others of the same age and sex.