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Waist size and body mass index (BMI)

Measuring your waist size

Carrying too much fat around your waist can increase your risk of heart disease, type 2 diabetes, cancer and stroke[1]. Check your waist size by wrapping a tape measure around the space between the bottom of your ribs and top of your hips. Guidelines on a healthy waist size differ for men and women.


Visit your GP for support with losing weight if your waist size is 102cm (40in) or more[1].


Visit your GP for support with losing weight if your waist size is 88cm (34.5in) or more[1].

Find out your BMI

Use this BMI calculator from the NHS to give you an idea of what a healthy weight range might be for you.

Things to bear in mind about BMI

  • The BMI calculator can't tell the difference between muscle, fat or bone[2].

  • Your BMI result doesn't take into account age, sex or muscle mass[2].

  • BMI calculator results don't apply if you have an eating disorder. Please speak to your GP, a pharmacist or NHS 111 for support[2].

  • If you're pregnant, you should enter your pre-pregnancy weight[2].


April 2021

Next review

April 2024

Reviewed by

Gill Stone MRPharmS


  1. 1.

    Why is my waist size important? Published June 26, 2018. Accessed March 1, 2021.
  2. 2.

    BMI calculator | Check your BMI. Published October 19, 2018. Accessed March 1, 2021.