BMI Calculator World Health Organization

This BMI calculator follows the World Health Organization (WHO) standards to help you determine your Body Mass Index (BMI) and understand its health implications. BMI is a widely used indicator of whether a person has a healthy body weight for their height.

What is BMI?

The Body Mass Index (BMI) is a measurement developed by the World Health Organization to assess whether a person has a healthy body weight relative to their height. It's calculated using a person's weight in kilograms divided by the square of their height in meters.

BMI Formula

BMI = Weight (kg) ÷ (Height (m) × Height (m))

The BMI categories established by the WHO are:

Underweight: BMI less than 18.5
Normal weight: BMI 18.5 to 24.9
Overweight: BMI 25 to 29.9
Obesity: BMI 30 or higher

While BMI is a useful screening tool, it doesn't directly measure body fat or muscle mass, so it may not be appropriate for athletes or individuals with very high muscle mass.

How to Use This Calculator

Using this BMI calculator is simple:

Enter your weight in kilograms in the weight field
Enter your height in centimeters in the height field
Click the "Calculate BMI" button
Review your BMI result and health category

For example, if you weigh 70 kg and are 170 cm tall:

Height in meters: 1.70
BMI = 70 ÷ (1.70 × 1.70) = 24.22
This would place you in the "Normal weight" category

Interpreting Your BMI

Your BMI result falls into one of these categories:

BMI Range	Category	Health Implications
Below 18.5	Underweight	May indicate insufficient weight, which can be a sign of malnutrition or other health issues
18.5 - 24.9	Normal weight	Generally considered healthy weight range
25 - 29.9	Overweight	May indicate excess body fat, which could increase health risks
30 or higher	Obesity	Significantly increased health risks associated with excess body fat

Remember that BMI is just one indicator of health. Other factors like muscle mass, bone density, and overall health should also be considered.

Limitations of BMI

While BMI is widely used, it has several limitations:

It doesn't distinguish between muscle mass and fat
It may not be accurate for athletes or people with high muscle mass
It doesn't account for age, sex, or overall health
It may not be appropriate for children or pregnant women

For more accurate body composition analysis, consider using other measurements like waist-to-hip ratio, skinfold thickness, or DEXA scans.

Frequently Asked Questions

Is BMI the only way to measure body fat?

No, BMI is just one indicator. Other methods like waist circumference, skinfold calipers, and DEXA scans provide more accurate body fat measurements.

Can BMI be used for children?

BMI charts for children are different from adult charts. The WHO provides specific BMI-for-age charts for children under 5 and 2-19 years.

Is a higher BMI always bad?

Not necessarily. Athletes and people with high muscle mass may have a higher BMI but still be healthy. BMI is just one indicator among many.

How often should I check my BMI?

For most people, checking BMI annually is sufficient. However, if you're making significant lifestyle changes, you might want to check more frequently.