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HealthInfo Canterbury

Finding out if I am a healthy weight

Working out your body mass index (BMI) is a good way to find out if you are a healthy weight.

Your BMI estimates how much body fat you have and also indicates your risk of getting diseases such as heart disease, type 2 diabetes, stroke, and some types of cancer. These are more common in people with more body fat, and the higher your BMI, the higher your risk.

Most people over the age of 18 can use BMI, but it does have some limits. It may:

Working out your BMI

You can work out your BMI using the following online BMI calculator from the NHS. You will need to know your weight in kilograms and your height in centimetres. The calculator will tell you if you are underweight, a healthy weight, overweight, or obese.

content provided by NHS Choices


After giving the BMI result, the calculator provides practical information about why the result matters. But the information is UK-based. Take a note of the BMI result, but instead of following the link that says "Why this result matters", read the local information below about the BMI result.

Your BMI result

Underweight (less than 18.5)

Being underweight could be a sign that you are not eating enough or that you have an underlying health issue. Make an appointment to see your GP or practice nurse. Find out more in How to gain weight.

Healthy weight (18.5 – 24.0)

Keep up the good work. For tips on maintaining a healthy weight see Eating well and keeping active for good health.

Overweight (25 – 29.9)

The best way to lose weight is by eating fewer calories than you need, and being more active. Find out more in How to lose weight.

Obese (30 and over)

The best way to lose weight is by eating fewer calories than you need and being more active. Find out more in How to lose weight.

If you are concerned about your weight talk to your GP or practice nurse.

Your waist size also matters

Measuring your waist is a good way to check you don't have too much fat around your stomach. You can have a healthy BMI and still have too much tummy fat, which can also raise your risk of heart disease, type 2 diabetes and stroke. You may need someone to help you with this.

To measure your waist:

  1. find the top of your hip bone and the bottom of your ribs (this is usually at the level of your belly button)
  2. wrap a tape measure around your waist midway between these points
  3. breathe out normally before taking the measurement

No matter what your BMI is, or how tall you are, you should try to lose weight if your waist is:

If your waist is:

you are at very high risk and should talk to your GP or practice nurse.

Written by HealthInfo clinical advisers. Last reviewed September 2017.


See also:

Being active to lose weight

Healthy eating to lose weight

How to lose weight

How to gain weight

Medications and surgery to help with weight loss

Weight-loss programmes and resources

Page reference: 45123

Review key: HIDIN-36726