Free BMI Calculator Online
Calculate your Body Mass Index with metric or imperial units
Quick BMI Assessment
Understand your weight status in seconds
Switch freely between kilograms and centimeters or pounds, feet, and inches depending on your preference.
See which WHO-defined BMI category your result falls into: underweight, normal, overweight, or obese.
View the healthy weight range for your specific height so you know your target.
About This Tool
Body Mass Index is a weight-to-height ratio, calculated as weight in kilograms divided by height in metres squared. It gives a single number used as a rough screening indicator for whether a person's weight sits in the underweight, healthy, overweight, or obese band as defined by the World Health Organization.
BMI is a population-level screening measure, not a diagnosis. It does not distinguish muscle from fat, so very muscular people can read as overweight, and it does not account for age, sex, or body composition. Treat the result as a starting point for a conversation with a health professional rather than a verdict on health.
It helps to read BMI alongside its context rather than in isolation. The same number means different things for a lean athlete, an older adult, and a growing teenager, which is why clinicians pair it with waist measurement, body composition, and history. Use the category as a prompt to look further, not as a conclusion about health.
How to Use It
- Enter your height and weight in metric or imperial units.
- Read your BMI value.
- See which WHO category it falls into, keeping the tool's limitations in mind.
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