How Do You Calculate BMI – The Ins and Outs of BMI | Home Cooking for Health

How Do You Calculate BMI – The Ins and Outs of BMI

Scale and measuring tape

BMI, or Body Mass Index, is a term that you might have heard but don’t know that much about. Doctors throw the term around especially when talking about health and health risks for diseases; but many may not know what it really means or how doctors come to the staggering results that they present to their patients.

We shall look at what BMI really is, the formulas explaining how do you calculate BMI, the history behind BMI, the difference between men and women, and some calculators for you to check what your own BMI is.

What is BMI?

Body Mass index is an attempt to categorize and chart the amount of body, including fat, muscle and bone, in the categories of underweight, normal weight, overweight, and obese.

BMI is gotten from a formula in relation to a person’s weight and height. Originally it was done in the metric system, but has been converted to imperial for ease of use.
The formulas go as follows:

Metric           weight(kg) ÷ height(m²) = BMI
Imperial       weight(lbs) ÷ height(in²) x 703 = BMI

The basis of BMI was actually developed between 1830 and 1850 by Adolphe Quetelet and had to do with what he called “social physics”. Later in 1972 the term Body Mass Index was coined in several writings and was described as “…at least as good as any other relative weight index as an indicator of relative obesity.”

What this really means is that your BMI, computed from using one of above formulas, is a simple way to calculate and give a numeric value to a person’s thickness or thinness. This gives your doctor a more object way to discuss your health and weight issues with you.

The Difference Between Men and Women, Besides the Obvious


Men and women are built differently. Men tend to have more muscle and women tend to have more fat. That is just how we are genetically predisposed by nature. Does BMI take this in to account?

As of right now, that is a nope. While there are many studies out showing that there could be different calculations for men and women, none of them agree on the exact numbers. Hence the CDC has just gone with a blanket formula that covers all adult men and women.

Honestly, this is a bit of relief to hear. Yes, I love to be exact and know exactly where I am and where I should be and what my goals should be, etc. Instead of that, I can have comfort knowing that I can give myself some wiggle room when choosing what my goals for weight should be. It’s not a hard number, but instead a range of where I will be healthy and lower my chance of getting preventable diseases such as hypertension and cardiac disease.

How Reliable is BMI?

While BMI is based on science, it is not flawless. It is a standardized way to classify yourself and one in which your doctor will use to determine your risks for diseases and health problems.

If you are exceptionally tall or short, the BMI might not work very well for you and your doctor should take that into consideration. This goes for the same for men vs women. Again, something your doctor should take into consideration and hopefully use a range instead of a hard number.

BMI Calculator – Find Out Where You Rank

Alright, let’s let the numbers do the work and see what your BMI really is with the CDC Adult BMI Calculator and how it stacks up on the chart.

I have also included a BMI calculator that takes into account gender and age as well.

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Here is a chart to help you see where your BMI puts you in a more detailed category.

Very Severely Underweight
Severely Underweight
Normal (healthy weight)
Obese Class 1 (moderately obese)
Obese Class 2 (severely obese)
Obese Class 3 (very severely obese)
Obese Class 4 (morbidly obese)
Obese Class 5 (super obese)
Obese Class 6 (hyper obese) #1
0 – 15
15 – 16
16 – 18.5
18.5 – 25
25 – 30
30 – 35
35 – 40
40 – 45
45 – 50
50 – 60
60 <=


As you climb higher in the BMI chart, the more likely you are to develop problems such as heart disease, hypertension, type 2 diabetes, gallstones, breathing problems, and certain cancers. More unknown is that if you are in the categories below normal you also run the risk of problems. These can include

BMI In a Nutshell

While BMI can be a finicky thing, it is really not that hard to understand. While helpful, it should be noted that this is an imperfect predictor of health risks related to your calculated BMI. It is a tool that is used by you and your doctor to help you get to a more healthy you.

You should always consult your doctor before changing your lifestyle and eating habits. Doctors can help you decide the best and most healthy way to go about getting the  results that you want in the safest way possible for you.

As always, please feel free to leave a comment if you have any questions or comments on what you just read. I always encourage people to ask when they aren’t sure of something and to gain a greater understanding of content.

Suggested Resources & Reading




    My little brother is really tall and as you said I am not sure BMI can provide accurate results for him or not. I wonder can you recommend an alternative?


      Angela K

      Here is a website that can give you a better idea of what a taller person’s BMI should be. The best thing you can really do is have your brother go to a doctor and get a test done that calculates body fat percentage. This would be the best and most accurate way to tell what the BMI of anyone is.



    What a nice post you wrote! I really enjoyed reading it and I could not be silent about your post so I decided to leave my comment here and say Thank You! For sharing this quality post with others.
    Actually this is exactly the information that I was looking for about how to calculate BMI and when I landed to your website and read this post, it answered all my questions in details.
    So I’m happy that you decided to write about this topic and share it with people. It’s very useful and can definitely be used as a great source for calculating BMI.
    I will come back to your website again for sure and I’m looking forward to read your new posts.)



      Angela K

      Thank you so much! I am so happy to hear that you found it helpful. It’s surprising how much misinformation is out there that can leave people wondering what is the correct information they should be following.


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