What is BMI | BMI Calculator | WW Canada

What is your BMI?


Body Mass Index (BMI) is a measure for weight-related health risk.


Check yours with our BMI calculator below.

About Body Mass Index

BMI under 18.5: Underweight
BMI 18.5 – 24.9*: Healthy weight
BMI 25 – 29.9: Overweight
BMI 30+: Obese


Calculate your BMI

BMI measures whether a person is at risk of overweight disease. But is BMI a reliable tool? Read about how WW looks at the matter.


What is BMI and what does it measure?


BMI is an abbreviation of Body Mass Index, and is a measure of weight-related health risk.

It is a tool that takes into account your weight in relation to your height in order to estimate the percentage of body fat. A high-fat percentage is clearly associated with increased risk of certain diseases such as cardiovascular disease, hypertension, Type 2 diabetes, respiratory problems, and some cancers.

Weight Watchers and Body Mass Index 

Body Mass Index is a good tool for determining weight-related health risks. It is available to everyone because it only requires a simple mathematical calculation. The result is also easy to understand and interpret. It's considered to be among the primary methods of measuring body fat, because other ways are often expensive and or difficult to access.


BMI is not always accurate

Of course there are times when BMI  is not the best method. It does not take into account gender or age, nor to the amount of bone, muscles and organs in the body. Therefore, it is also not a crucial measure for certain groups, such as athletes and bodybuilders. For these people, it is more fair to use other methods that take into account the actual dimensions of the body. Many of these are quite demanding and you need to measure repeatedly to get a fair score.

How WW can help


WW Freestyle is a safe way to lose weight. At the beginning of your weight journey it may valuable to be aware of your Body Mass Index , so you have an idea of your health risks in relation to your weight. With the help of WW, we recommend that you lose weight at a rate of 1-2 lb per week, without having to count calories or going hungry.


Feel free to measure your waist size to get a more complete picture of your weight. How to use:

  • Use a tape measure
  • Measure the waist in height with the navel, midway between the lower rib and the hip leg. Measure the waist in height with the navel, midway between the lower rib and the hip leg
  • Stand relaxed with your legs slightly apart. Take a deep breath and breathe out just before you measure
  • Measure without tightening the tape measure

Abdominal fat is defined as a waist measurement over 32"/88 cm in women and over 40"/102 cm in men.

However, even at a waist size of 31"/80 cm in women, there may be an increased risk of cardiovascular disease. At 37"/94 cm in men, there may be increased health risk in combination with other risk factors.


*WW is committed to be a responsible provider of programs and services that inspire healthy habits for real life. We have specifically chosen to be conservative in our policies and procedures and, as such, have a “floor” on our healthy weight range of a BMI of 20. This is done for two reasons. First, the weight ranges serve to assess eligibility for membership and require that a potential member be at least 5 pounds above the minimum weight. If we used a BMI of 18.5, individuals who are already at a lower weight would be eligible to join. Second, we encourage people to attain ultimate weight goals that are realistic and sustainable.

Start your weight loss journey today