How body mass index is measured?

Body mass index (BMI) is a measure that evaluates the ratio between a person's weight and height, and categorizes them into different weight groups based on whether their weight is considered healthy or not. BMI is calculated using the following formula:

BMI = Weight (kg) / Height² (m²)

- Weight: Refers to a person's body weight measured in kilograms (kg).

- Height: Represents a person's height measured in meters squared (m²).

Here's a step-by-step explanation of how body mass index is calculated:

1. Convert Weight to Kilograms:

- If your weight is measured in pounds (lbs), you must convert it to kilograms by dividing your weight in pounds by 2.20462.

2. Calculate Height in Meters:

- If your height is measured in inches, you must convert it to meters by dividing your height in inches by 39.37.

- Alternatively, if your height is already in centimeters, divide by 100 to convert it to meters.

3. Calculate Body Mass Index:

- Once you have the weight in kilograms and height in meters, use the formula:

BMI = Weight (kg) / Height² (m²).

4. Interpret BMI:

The resulting BMI value falls into one of the following categories:

- Underweight: BMI < 18.5

- Normal weight: BMI between 18.5 and 24.9

- Overweight: BMI between 25 and 29.9

- Obesity (Class I): BMI between 30 and 34.9

- Obesity (Class II): BMI between 35 and 39.9

- Extreme Obesity (Class III): BMI ≥ 40

BMI provides a quick and useful indicator of whether a person's weight is within the healthy range. It should, however, be interpreted with caution, as BMI alone doesn't take into account muscle mass, age, sex, ethnicity, and other factors that can influence body weight. Nonetheless, it serves as a widely accepted tool for assessing overall weight status in general population health assessments.