Using A BMI Calculator During Weight Loss

BMI can be a useful tool during your weight loss efforts as long as you know how to use it correctly. The two main mistakes that people make with BMI are either placing too much weight in its results or completely abandoning it altogether. The reality is that BMI is a great indicator for your progress, but needs to be used alongside other factors in order to give you a complete picture of what’s going on with your body.

bmi calculator

BMI stands for Body Mass Index and refers to a certain set of categories you’re placed into based upon a value created from your height and weight. These categories are:

  • Under 18.5 – This value means that you’re underweight and possibly, malnourished.
  • 18.5 to 24.9 – This is the healthy range for adults to be in, meaning that your weight is at a good level for your height.
  • 25 to 29.9 – If you’re in this category, then you’re considered overweight, but not obese.
  • Over 30 – This refers to those who are clinically obese and therefore, their weight is a severe threat to their health.

Now, in terms of weight loss, BMI can be an incredibly useful tool for those who are overweight or obese as it can show your progress through each categories and therefore, the progress you’re making towards a healthier body.


For those who have a regular bodyweight and simply want to lose a little fat, then it’s useful to also take progress pictures or body fat measurements whilst tracking your gym progress. Ideally you want your strength or physical capabilities to stay relatively the same as you lose weight so that you know the weight is coming from fat and not muscle. You may lose a little strength, but that’s to be expected. However, if you start losing large chunks of strength and your BMI is falling drastically, then you know you might need to change up your weight loss methods.


With BMI, you don’t need to check it as often as you weigh yourself. Here is an easy guide to how often you should check your progress:

  • Weight – Twice per week
  • Progress pictures – Once per week
  • Fat percentage – Once per week
  • BMI – Once every two weeks

By doing all of these, you’re ensuring that you’re not only making some progress, but good progress, knowing that the weight is coming from the right place.


At the end of the day, BMI isn’t a necessary tool, but it can provide some helpful extra data to give you a better picture of your body and your health. It also takes very little time with the help of an internet calculator. Simply type ‘BMI calculator’ into your chosen search engine and a variety of options will all pop up. Try to find one that takes into account your gender and age as well as your height and weight as these additional factors can skew your results slightly if not included.