BMI Calculator
Calculate your Body Mass Index with metric or imperial units
Enter your weight and height above to calculate your BMI.
What is BMI?
Body Mass Index (BMI) is a simple numerical measure of a person's weight relative to their height. It is calculated as weight (kg) divided by height squared (m²). BMI is widely used by healthcare professionals as a screening tool to identify potential weight-related health issues. While it doesn't directly measure body fat, it correlates reasonably well with direct measures of body fat for most people.
BMI Categories (WHO Standard)
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obese (Class I) |
| 35.0 – 39.9 | Obese (Class II) |
| 40.0 and above | Obese (Class III) |
Frequently Asked Questions
Is BMI accurate for everyone?
BMI is a general screening tool and has limitations. It may overestimate body fat in athletes and people with high muscle mass, and underestimate it in older adults who have lost muscle. It also doesn't account for fat distribution or differences across ethnicities. Consult a healthcare professional for a full health assessment.
What is a healthy BMI range?
According to the WHO, a BMI between 18.5 and 24.9 is considered normal weight for adults. For some Asian populations, the healthy range may be slightly lower (18.5–22.9).
Does BMI apply to children?
BMI for children (ages 2–19) is interpreted differently using age- and sex-specific percentile charts. This calculator is designed for adults aged 20 and older.