[Skip to content]


Body Mass Index

What is your BMI?

The healthy weight range is based on a measure called the body mass index (BMI). This is measured from your weight and your height in order to see if you have a healthy level of body fat. The higher your BMI level, the more your weight can affect your health, putting you at greater risk of diabetes, heart disease, cancer and other health problems.

Being a healthy weight is all about the energy balance- if you eat more calories than you use in daily activities and exercise, the spare energy is stored as fat on your body and your weight increases.

Please note: A BMI measure is not as accurate if you're an athlete or very muscular as muscle is heavier than fat and can push you into a higher BMI level even if you have a healthy level of body fat. It is also not accurate for women who are pregnant, breast-feeding, people who are frail or children.

To find out your BMI, fill in your weight and height below and the calculator will do the rest
Body Mass Index Chart
Details of how your weight is assessed on the BMI Chart.
Underweight BMI less than 18.5
Ideal BMI 18.5-24.9
Overweight BMI 25-29.9
Obese BMI 30-39.9
Very obese BMI 40 or more

BMI Healthy Calculator - From NHS Choices website for Public Health content

BMI calculator and tracker iPhone app

Go to NHS Choices homepage