- What is Body Mass Index (BMI) ?
- What is your BMI?
- How to interpret BMI calculations?
- BMI for teens and for kids
- Limitations of bmi method
Until 1972, when the well known term “body mass index” was mentioned, it was previously known as the Quetelet Index and was first introduced by the Belgian mathematician, astronomer Adolphe Quetelet.
Body mass index more commonly known as BMI is a measure of fatness based on body mass in relation to your body height, and allow to classify weight related health risk for most adult men and women aged 20 and over.
What is your BMI?
There are few ways to determine your BMI
Metric BMI calculation formula
You can find out your BMI using standard formula:
BMI = Body Mass / ( Body Height * Body Height)
Where Body Mass measured in (kg) and Body Height measured in (m)
Imperial BMI calculation formula
To calculate BMI using imperial system you need to make a small conversion, now formula will look like:
BMI = ( Body Mass * 703 ) / ( Body Height * Body Height)
At this time Body Mass measured in (lb) and Body Height measured in (inches)
Using BMI calculator
There are a lot of different calculators over the net which can help you to calculate bmi, but right now you can try our advanced bmi calculator online. It allows you to make calculations in both metric and imperial systems.
How to interpret BMI calculations
Body mass index has it’s own categories which can help you to classify current fatness state of your body. Here they are:
| Category | Range |
| Very severely underweight | <15 |
| Severely underweight | 15-16 |
| Underweight | 16-18.5 |
| Normal or healthy weight | 18.5-25 |
| Overweight | 25-30 |
| Obese | 30-35 |
| Obese class 2 | 35-40 |
| Obese class 3 | 40-45 |
| Obese class 4 | 45-50 |
| Obese class 5 | 50-60 |
| Obese class 6 | >60 |
If you BMI value is lower then 18.5 (underweight) that means that you may be malnourished or have a higher risk to get respiratory disease, digestive diseases or compromised immune function.
If you BMI value is greater then 25 (overweight) and physically inactive, that means that you may have higher risk to get cardiovascular disease, high blood pressure, diabetes and mental health disorders.
BMI for teens and for kids
For children and teens BMI calculated in the same way as it is for adults, but obtained value is interpreted using special charts based on sex-specific BMI/age charts. This is because due to the fact that the body is at the stage of formation and body fat changes with age for children and teens. Also, new researches have shown that females aged 12 to 16 years, have BMI is higher than males in the same age category.
Here is bmi classification categories for children over 2 years:
| Category | Range |
| Underweight | > 5 % |
| Healthy weight | 5-85 % |
| Overweight | 85-95 % |
| Obese | > 95 % |
Limitations of BMI method
Despite the fact that the bmi formula is quite popular, it still has a number of limitations and not in every case, this formula provides fairly accurate results.
First of all BMI formula doesn’t take into account difference between muscle and fat mass. Usually professional athletes or bodybuilders, whom have low fat percentage and high muscle mass, which is explained by their way of life, may have higher bmi which will show incorrect state like overweight or obesity.
Another factor which doesn’t taking into account by bmi formula is physical disabilities – people whom have some physical disabilities may have lower mass through amputations and in their case bmi will show incorrect results.
Height is third factor, which you must pay attention to when calculating your bmi. Formula have tendency to overestimate obesity of smaller people and underestimate it’s value for taller people.