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This content is taken from the University of Reading's online course, Obesity: Causes and Consequences. Join the course to learn more.

Calculate your own weight parameters

You can measure your own BMI and waist circumference ratio at home.


In the UK the NHS have an online calculator for BMI. You’ll need to know your weight (in kilogrammes or stones and pounds) and height (in centimetres or feet and inches) to use the calculator.

There is also an interesting comparison tool on the BBC website, which allows you to compare your BMI with the average for your country and the rest of the world.

Waist circumference

To find your true waist, feel for your hip bone on one side. Move upwards until you can feel the bones of your bottom rib. Halfway between is your waist. For most people this is where their tummy button is. Use a mirror the first time to see what you’re doing and to make it easier to measure.

How to measure waist circumference

Waist-to-hip ratio

  1. Measure your waist.
  2. Measure your hips.
  3. Divide your waist measurement by your hip measurement. This works for measurements in centimetres and inches.

Ideally, the number should be below 1.0 for men or 0.85 for women.

Waist to hip calculator

Waist-to-height ratio

  1. Measure your waist.
  2. Measure your height.
  3. Divide your waist measurement by your height. Again, this works for measurements in both centimetres and inches.

Below 0.5 is considered to be healthy, whereas a number above 0.5 suggests that you’ve got too much visceral fat.

Waist to height ratio calculator

Having calculated your actual measurements, you can play around with the numbers to see what effect any increase or decrease in weight or waist/hip measurement would have. We’re assuming you can’t change your height!

Please don’t feel you have to share your actual results here. It is more the generalities of the different options that we want you to think about.

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This article is from the free online course:

Obesity: Causes and Consequences

University of Reading