# How to calculate BMI

Learn how to calculate your BMI and how to find your weight category.

Your body mass index is a measurement which determines which weight category you belong to, and it will give you an idea of how your weight compares to common values.

- Underweight (BMI less than 18.5)
- Healthy weight (BMI 18.5 to 24.9)
- Overweight (BMI 25 to 29.9)
- Obese (BMI 30 and above)

But... how can you calculate your BMI? The formula is easy to compute. In fact, the simplicity of the BMI formula is part of the reason for its success.

**BMI Formula Limitations:**

The Body Mass Index does not take into account other factors which may affect your height and weight:

- Body Builders.
- Pregnant women (or lactating).
- Children and teenagers.
- Natural differences between races.

## Metric method

To calculate your BMI you will need your weight measurement in kilograms and your height in meters.

If you know your height in centimeters only, simply divide the number of centimeters by 100 to convert it to meters.

Example: My height is 180cm = 1.80M (180cm/100=1.80m)

The metric formula is even easier than the imperial method, just follow the two step process:

- Multiply your height by itself (height x height)
- Divide your weight by the value calculated in step 1

**Example:**

- My height: 1.80m

- My weight: 75Kg

Step #1= 1.80 x 1.80 = 3.24

Step #2= 75 / 3.24 = 23.14

The resulting number (23.14) is your Body Mass Index.

Now compare this BMI value with the weight categories and find you are at a healthy weight.

## Imperial (US) method

To calculate your BMI you will need your height measurement in inches and your weight in pounds

If you know your height in feet and inches, you will need to multiply your number of feet by 12 and add them to the number of extra inches.

Example: My height is 5 feet and 11 inches = 71 inches (5 x 12 = 60 and 60 + 11 = 71)

Now, just follow the 3 step process:

- Multiply your weight by 703
- Multiply your height by itself
- Divide the figure in step 1 by the figure in step 2

**Example:**

- My height: 71 inches

- My weight: 165 pounds

Step #1= 165 x 703 = 115,995

Step #2= 71 x 71 = 5,041

Step #3= 115,995 / 5,041 = 23.01

The resulting number (23.01) is your Body Mass Index.

Now compare this BMI value with the weight categories and find you are at a healthy weight.

## Calculate now your BMI

You can calculate your body mass index to know if you are underweight or within the normal weight range.