Body mass index (BMI) is a good measure to determine if you are malnourished, overweight, or obese. It represents your weight in relation to your height. Here are 5 things you should know about BMI.

"Body, Mind, Intellect and Body Mass Index. If perfect, you are ready to conquer the unseen." - Kansy.

BMI and 5 things you should know

1. How to measure BMI?

BMI can be calculated in two units: metric and imperial. 

How to calculate BMI - BMI formula

Metric units formula:

BMI= Weight in kilograms / Square of height in meters

For example, if your weight is 45 kg, and your height is 1.54 m, your BMI = 45/2.37.

Imperial units formula:

BMI = 703 x Weight (lbs) / Square of height in inches

If you want to skip the math, you can use our BMI calculator to quickly check your BMI and find out if you're at a healthy weight.

2. What’s a normal BMI?

BMI is commonly used to assess how far your body weight departs from what is normal for your height. A normal BMI is between 18.5 and 25. 

The WHO (World Health Organization) considers a person with a BMI of less than 18.5 as underweight. It may also indicate malnutrition, an eating disorder, or some other health problems. A person is considered overweight if the BMI is between 25 and 30. And over 30 is considered obese. 

Body Mass Index Category 

BMI Weight Status

Below 18.5: Underweight

18.5-24.9: Healthy Weight

25.0-29.9: Overweight

30.0+: Obese

3. The higher your BMI, the higher the risk for your health problems

The WHO regards a high BMI as one of the major risk factors for several health problems including:

  • heart disease
  • stroke
  • diabetes
  • arthritis
  • several types of cancer (breast, colon, and endometrial cancer)
  • bone and joint problems such as osteoarthritis
  • high blood pressure
  • high cholesterol

There are many studies suggest that over 365,000 deaths due to obesity each year in the U.S. According to recent research, those with high BMIs report that they feel better both physically and psychologically when they return to normal BMI range. 

4. If you have a high or low BMI, consult your doctor

If you have a high or low BMI, you should talk to your doctor to determine if you have any underlying health problems. A sudden change in weight can be a symptom of many diseases. 

Your doctor may set you up with a suitable diet or prescription to help you get back on track. 

5. BMI isn't the only factor that you should consider

"BMI tells you how "big" you are, not how "sick" you are."

BMI is just one factor to determine your overall health. So you don't have to worry much about your health when you find out that you're not in a normal range of BMI.

A high BMI doesn't always indicate that you are overweight. This calculation doesn't account for muscle mass. People with high muscle mass often have high BMI even if they are not overweight. This is because muscle weighs more than fat. 

So BMI, as a single measure, would not be expected to identify cardiovascular health or illness. 

To determine if you are in good health, you should consider BMI along with other factors such as blood pressure, blood lipid levels, and other important signs of wellness.