BMI Calculator
Work out your Body Mass Index in centimetres and kilograms, feet and stones, or pounds, and see the healthy weight range for your height.
About this tool
Body Mass Index is your weight in kilograms divided by the square of your height in metres. For adults, the NHS treats under 18.5 as underweight, 18.5 to 24.9 as a healthy weight, 25 to 29.9 as overweight, 30 to 39.9 as obese and 40 or above as severely obese. People from some ethnic backgrounds have a higher risk of conditions such as type 2 diabetes at a lower BMI, so the NHS uses lower thresholds for them: tick the box to apply those (overweight from 23, obese from 27.5).
BMI is a quick screening measure, not a diagnosis. It can't tell muscle from fat, so very muscular people can read as overweight, and it doesn't show where weight is carried; your waist measurement (ideally less than half your height) adds useful information. It isn't suitable for children, teenagers or pregnant women, whose BMI needs age-specific charts or a midwife's advice. Your chosen units are remembered in this browser.