BMI Calculator
Your Body Mass Index is a quick way to check whether your weight is in a healthy range for your height. Switch between metric and imperial as you like.
Body Mass Index
Work out your BMI
About BMI
What does BMI actually measure?
BMI is your weight in kilograms divided by the square of your height in metres. It's a quick, population-level guide — useful as a starting point, but it doesn't account for muscle mass, age, body composition or where fat is carried.
The standard NHS categories are: under 18.5 (underweight), 18.5–24.9 (healthy), 25–29.9 (overweight) and 30+ (obese). If your result sits near a boundary, speak with a healthcare professional for context that fits you — including waist measurement, blood pressure and other markers.