BMI Calculator | Calculate your Body Mass Index

BMI Calculator is a tool to measure someone’s body fat. The Body Mass Index Calculator calculates individual's height and weight. The measurement result can reveal an individual’s weight condition as per BMI Chart. BMI is generally classified into three categories such as underweight, normal weight and overweight / obese. However, there are more other categories that give more understandings. These categories are based on the WHO guidelines.  Therefore, the calculator uses six categories such as underweight, normal, pre-obesity, obese I, obese II and obese III.

Here is the BMI calculator.

Height

Weight

75

The BMI is:

Underweight

A person classified as underweight when their BMI is below 18.5. It may due to a variety of reasons such as genetics, underlying medical condition or unhealthy diet. The underweight may cause health problems including weakened immune system, osteoporosis and infertility.

Normal

A person is classified as normal when the BMI ranges is between 18.5 and 24.9. The normal weight is associated with a lower risk of chronic diseases. He/she may free from heart disease and type 2 diabetes.

Pre-obesity

A person is classified as pre-obese when their BMI falls between 25 and 29.9. The pre-obese may increase the risk of health problems. Type 2 diabetes, high blood pressure and high cholesterol could be issues. It was earlier classified as "overweight".

Obese I

An individual is classified as obese class I when their BMI falls between 30 and 34.9. Obesity class I is associated with an increased risk of health problems. Heart disease, stroke and certain types of cancer are notable problems.

Obese II

A person is classified as obese class II when their BMI falls between 35 and 39.9. Obesity class II is associated with an even greater risk of health problems.

Obese III

An individual is classified as obese class III or morbidly obese when their BMI is 40 or higher. Obesity class III is associated with the highest risk of health problems and it may harm health.

How to use it?

First of all, you have measure your height and weight. You have to measure the height in centimeter / feet, and weight in kilogram (kg).  Generally, Sri Lanka uses feet and inches to measure height as well as centimeters. Sri Lanka uses kilogram to scale weight. Therefore, the calculator available in feet (and inch), and centimeter (cm) and kilogram.

Move the “Height” slider and stop where it appropriate to your height. If you confusion on measurement, you can use the centimeter to feet convertor.

Move the “Weight” slider and stop where it indicate to your weight in kg.

Find your BMI value, and know the condition of your Body Mass Index which could be fixed into the following classifications:

BMI Chart (World Health Organization guidelines)

BMI Categories	BMI Values
Underweight	< 18.5
Normal weight	18.5-24.9
Overweight	25-29.9
Obesity class I	30-34.9
Obesity class II	35-39.9
Obesity class III	≥ 40

How does the calculator work?

BMI calculates using a common formula that takes into account of someone's weight and height. Again, it compares with the WHO’s BMI categories (refer above table) and display the result. The calculation formula of is:

BMI = weight (kg) / height (cm)^2

Example: John's weight is 88 kg and height is 172.5 cm (5 feet 8 inch). To calculate his BMI, we can divide his weight by his height squared and the result is 29.57. Formula: 88 kg / (172.5 cm) ^2 = 29.57. 

If you calculator does not have square (^), you can follow the alternate method. It is BMI = (88 / 172.5 / 172.5) x 10000, and the method is (kg / cm / cm) x 10000. 

As per the example, John's BMI is 29.57, which falls within the pre-obesity range.