Body Mass Index (BMI)

What is the BMI measurement?

The BMI or body mass index measurement is a calculation of the ratio between your height and weight, which can give you an accurate idea as to whether your overall body weight is healthy. The BMI measurement is commonly used by GP's and medical professionals, as well as the National Institute of Health and The World Health Organization as a way to determine whether someone is obese.

This calculation is considered by health experts to be the most useful way of assessing and measuring your weight, as people's body frames are naturally different. The body mass index works by recommending a healthy weight range for your height, as opposed to one particular weight for your age group.

Why should I know what my BMI is?

You can work out your body mass index by either using our BMI calculator or you can find out your BMI while doing your online consultation. Alternatively, you can do the calculation yourself. For details on how to do this see the 'What is the BMI calculation?' section below.

It's important to find out your BMI calculation because if you fall within the overweight or obese category you have an increased risk of developing a range of chronic health conditions, such as hypertension, type 2 diabetes, coronary heart disease, gallbladder disease and osteoarthritis. You are also more likely to suffer a stroke or heart -attack. Your risk of developing endometrial, breast, prostate and colon cancer is also significantly heightened compared to if you were in the healthy weight category.

What is the BMI calculation?

The BMI calculation is done by taking your height in metres, and multiplying this number by itself - your height squared. You then need to work out your weight in kilograms, and divide your weight by your height squared.

For example, if your height is 5ft 3in, this would equal 1.6 metres. If your weight is 10st 3lbs, this would equal 65kg. Your BMI calculation would be:

1.6m x 1.6m equals 2.56. Take your weight in kilograms, 65, and divide this by your height squared (2.56). This equals 25.39.

What does the outcome of my calculation mean?

If the number you calculate is below 18.5 you fall within the underweight category, and should gain a sensible amount of weight so that you reach the healthy weight range. The healthy weight range is any number between 18.5 and 24.9. If you fall within this range, you are the ideal weight for your height.