BMI Calculator
Free BMI calculator to calculate your Body Mass Index. Get instant results with our easy-to-use BMI calculator. Supports both metric and imperial units.
About BMI
Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity in adults.
BMI is calculated using your weight and height. It does not directly measure body fat, but it provides a quick, widely used way to group people into ranges that are useful for population-level statistics and general guidance.
BMI formula
Metric: BMI = weight(kg) ÷ [height(m)]²
Imperial: BMI = 703 × weight(lb) ÷ [height(in)]²
BMI range at a glance
< 18.5
18.5 – 24.9
25 – 29.9
≥ 30
The colored bar is a visual guide only. BMI ranges may be interpreted differently depending on age, sex, ethnicity and individual health conditions.
Limitations of BMI
BMI does not distinguish between muscle and fat, and it does not account for how fat is distributed around your body. Athletes with high muscle mass can have a "high" BMI while still being very lean and healthy.
For that reason, BMI should be treated as a simple starting point, not a diagnosis. If you are concerned about your BMI or weight, it's a good idea to discuss it with a healthcare professional who can look at the full picture.