Body mass index (BMI) – How do I calculate it?

Your body mass index is important because it allows you to determine your risk level for major dangers like cancer, stroke, heart disease and diabetes. All of these conditions are more likely to strike and kill you if you are obese.

To calculate your body mass index, or BMI, doctors compare your height to your weight. I say doctors do this, but –really– anyone can do it. You can do it for yourself.

BMIMy friend Jack is overweight, but he carries it well. He once told me with indignation that, “By my BMI, I’m considered obese!” He emphasized the word “I’m” to show how silly this was.

What he doesn’t understand is that the numbers aren’t wrong. Only his idea of what the word “obese” means is wrong.

Jack thinks the word “obese” only applies to the heaviest people on earth, people like Michael Hebranko, who weighs in at more than 1,100 pounds (500 kg). But “obese” just means that your body mass index number is from 30 to 39. If your body mass index is higher, you —like Mr. Hebranko— qualify for “extreme obesity.”

If you are more than 50 pounds overweight, then there is no doubt about it, you are obese. It doesn’t matter if some other people carry more weight than you. All those scientific studies that calculate the health risks that go with obesity apply to you. It’s as simple as that.

Learn how to calculate your own body mass index using this link.

Basically, if you are the same weight as a  typically healthy person of the same height, your body mass index falls into the normal range. If you are heavier, then your body mass index is higher, putting you into one of three categories you’d really rather not be in: Overweight, Obese or Extremely Obese.

For example, I’m 72 inches tall and I weight about 169 pounds. That gives me a body mass index of 23, which is in the normal range.

My friend Jack is 75 inches tall and weighs about 250 pounds. That gives him a body mass index of 34, which is in the obese range.

Your weight and height are all you need to calculate your body mass index.

Body mass index is a useful calculation. Clearly it is not always absolutely exactly right, but that doesn’t mean you can’t rely on it for a guideline to how healthy you are. There are two typical cases when a body mass index calculation can be a little off base:

If you are extremely muscular, you may have a higher body mass index, which overestimates the amount of fat you are carrying.

If you are elderly, you probably have lost some muscle. This is what naturally happens to us all as we age. In your case, the body mass index calculation may underestimate your body fat and give you too positive a picture of your health.

What You Can Do Today

If you haven’t calculated your body mass index yet, I encourage you to do it now. Write it down, and keep track over time.

The next time you reach for an after-dinner cookie, the thought might pop into your head, “If I skip this cookie, it might help me get my body mass index down.”

Don’t expect too much. However, something as simple as writing down your body mass index can help motivate you to make small changes that over time could help you lose weight.

Free Resources:

Free Worksheet: Calculate Your Body Mass Index
Free Daily Food Log: Help Yourself Eat Better and Lose Weight
Free E-Newsletter: Stay Motivated, Keep Learning
Free Weigh Loss Quote of the Day or Quote of the Week: Get Inspired Again, and Again, and Again...


  1. Labo Falk says:

    If, having said that, you rather utilize the BMI calculator to match the body compositions of both of these different persons, you should think of equivalent body fat percentages. By utilizing the BMI calculator as being a way of way of measuring there couldn’t end up being the superb disparity that you simply would see utilizing sheer weight as being a measurement.


    Take Care

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