We use cookies to improve your experience. By continuing to use this site, you agree to our use of cookies.
Calculate your Body Mass Index (BMI) to check if your weight is in a healthy range. Free, instant, and accurate.
Body Mass Index (BMI) is a simple calculation using a person's height and weight. The BMI value is a moderately reliable indicator of body fatness for most people. It was devised in the 1830s by Belgian mathematician Adolphe Quetelet and remains one of the most widely used health screening metrics worldwide.
BMI is calculated by dividing your weight in kilograms by your height in meters squared (BMI = kg/m²). For example, a person weighing 70 kg with a height of 1.75 m would have a BMI of 70 ÷ (1.75 × 1.75) = 22.9. Our calculator handles both metric and imperial unit conversions automatically.
| Category | BMI Range |
|---|---|
| Underweight | < 18.5 |
| Normal Weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese (Class I) | 30.0 – 34.9 |
| Obese (Class II) | 35.0 – 39.9 |
| Obese (Class III) | ≥ 40.0 |
While BMI is a useful screening tool, it has important limitations. It doesn't distinguish between muscle and fat mass, meaning athletes may be classified as overweight despite having low body fat. BMI also doesn't account for age, sex, ethnicity, or body fat distribution. For a more comprehensive health assessment, consider combining BMI with other measurements like waist circumference, body fat percentage, and blood test results.