Calculate adult Body Mass Index (BMI) using height and weight. The result includes the standard category and a general healthy-weight range for the height entered.
BMI Calculator
Enter your height and weight to calculate your Body Mass Index.
Results are estimates for general information only. Food portions, recipes and individual needs vary. This tool is not medical advice.
How BMI is calculated
BMI is weight in kilograms divided by height in metres squared. Standard adult categories commonly describe a BMI below 18.5 as underweight, 18.5–24.9 as healthy weight, 25–29.9 as overweight and 30 or above within the obesity range.
Limits of BMI
BMI is a screening measure rather than a diagnosis. It does not distinguish muscle from fat and may not reflect individual health risk accurately for athletes, during pregnancy or in some ethnic groups. Waist-to-height ratio and professional assessment may add useful context.
Frequently asked questions
Is BMI suitable for children?
This calculator uses adult categories and is not designed for children or teenagers.
Can muscular people have a high BMI?
Yes. BMI may classify a muscular person as overweight because it does not measure body composition.
What should I do about a concerning result?
Use it as a prompt to discuss your weight and wider health with a GP or another qualified professional.
Further reading: NHS information on weight and BMI.