Calculate your Body Mass Index instantly. Supports both metric and imperial units and shows your healthy weight range.
Body Mass Index (BMI) is a simple calculation using a person’s height and weight. The formula is BMI = kg/m². It is widely used as a screening tool to categorize weight status.
BMI does not directly measure body fat. Athletes with high muscle mass may have a high BMI while remaining healthy. Older adults or people with low muscle mass may have a normal BMI despite higher body fat. Always consider additional measures such as waist circumference or body fat percentage.
For most adults, a BMI between 18.5 and 24.9 is classified as normal weight by the WHO. BMI is a screening tool only — athletes and people with high muscle mass may have a higher BMI without excess fat.
BMI = weight (kg) ÷ height (m)². Example: 70 kg and 1.75 m → 70 ÷ (1.75 × 1.75) = 22.9. This calculator does the conversion and classification for you.
BMI does not measure body fat directly. It can misclassify muscular people, older adults, and some ethnic groups. Use it with body fat, waist size and how you feel for a fuller picture.
Overweight is typically 25–29.9. Obesity starts at 30. These ranges are general guidelines, not a diagnosis. Talk to a clinician for personal health decisions.