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What Is Your BMI?

If you are starting to lose weight and get healthy, you may come across some phrases and abbreviations that you don't understand. BMI is commonly used when discussing health and fitness and it is really quite simple!
What is the BMI?
The body mass index (BMI) is a formula which calculates your body mass using height and weight and gives an indication of health risk and longevity. It is by no means a perfect formula because it doesn't take into account whether your weight includes a high or low percentage of body fat, nor where fat is distributed over the body. For example, carrying a lot of fat around your waist is more of a health risk than carrying it on your hips and thighs.
Nonetheless, it is a good guide. Generally speaking, a Body Mass Index figure of 20-25 is considered the normal healthy range. Between 25-30 you should aim to prevent any further gain and think about losing some weight. If it's over 30, you really should be making some changes to your lifestyle that will help you lose weight. At over 40, your health could be at serious risk. Equally, being very underweight, a BMI of 18.5 or less, is also a health risk.
Who can use the BMI?
The health risks are the same for both men and women, but the formula does not apply to children under 18 nor to women who are pregnant or breastfeeding. It may not be accurate for athletes who have a high proportion of muscle mass, or for over-60s who may have lighter bones through bone loss.
How do I calculate my BMI?
The BMI formula is worked out from your weight in kilos divided by your height in metres squared. 

To work out your own BMI, firstly you should find a calculator and follow each step below:

  • To work out your current weight in kilos, multiply the stones by 14 then add on the pounds. Now multiply your answer by 0.4536 to convert your weight into kilos.
  • To work out your height in metres, multiply feet by 12 and add on the inches. Now multiply your answer by 0.0254 to convert your height into metres.
  • Now multiply your height in metres by itself (height in metres times height in metres).
  • To find your BMI, divide your weight in kilos (answer to step 1) by your height in metres squared (answer to step 3).
If the calculation is too taxing for you, don't worry! You can use this handy chart as a guide to your BMI:
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