What is BMI? – BMI Calculator

Body Mass Index (BMI) is a simple measure that relates your weight to your height. It is calculated as weight in kilograms divided by height in metres squared (kg/m²), and it is the most widely used quick check of whether a person's weight is in a healthy range.

Doctors and public-health organizations use BMI because it is fast, free and needs only two measurements. Your result places you in one of four categories defined by the World Health Organization. See the Categories tab for the full table.