NHS Health Check

Helping you prevent heart disease, stroke, diabetes and kidney disease

Understanding your BMI

Understanding your BMI

At your NHS Health Check, your body mass index (BMI) will have been measured. If it fell outside the healthy range, your GP or health professional may have discussed this with you.

BMI is a measure of whether you're a healthy weight for your height.

You can learn more about how BMI is measured, and why it matters, in BMI: the test.

Your BMI

For most people, the healthy BMI is between 18.5 and 24.9.

There are exceptions to this general rule. Athletes who have very large muscles, for example, can have a BMI of 25 or over without carrying excess weight.

But for most people, a BMI of 25 or over indicates that you may be carrying excess weight, and that your health would benefit if you lost weight.

A BMI below 18.5 indicates that you may be underweight. This could be a sign that you’re not eating a healthy and balanced diet that contains enough energy for your needs. Or it may be a sign of a wide range of underlying health conditions.

Take action

If your NHS Health Check revealed a BMI of below 18.5 or above 24.9, your GP or health professional will have discussed this with you.
It’s important that you stick to any plan that you and your health professional put together.

There’s lots of advice and information on NHS Choices that can help. Learn more in Achieve a healthy weight.

Last reviewed: 23/05/2011

Next review due: 23/05/2013