World Health Organisation BMI Calculator

The World Health Organisation BMI Calculator helps you determine your Body Mass Index (BMI) using the WHO's standard method. BMI is a simple calculation that provides a general indication of whether a person has a healthy body weight for their height.

What is BMI?

Body Mass Index (BMI) is a value derived from the mass (weight) and height of an individual. The BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m², resulting from mass in kilograms and height in metres.

BMI Formula

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

The BMI is a convenient rule of thumb used to broadly categorize a person as underweight, normal weight, overweight, or obese based on tissue mass (muscle, fat, and bone) and height. It's important to note that BMI does not measure body fat directly, but it's a widely used indicator of overall body composition.

How to Use This Calculator

Enter your weight in kilograms in the "Weight" field
Enter your height in meters in the "Height" field
Click the "Calculate" button
View your BMI result and category

The calculator will display your BMI value and the corresponding WHO category. You can also see a visual representation of your BMI on the chart.

BMI Categories

The WHO categorizes BMI into the following groups:

BMI	Category	Health Risk
Below 18.5	Underweight	Potential nutritional deficiency and osteoporosis
18.5 - 24.9	Normal weight	Low risk (healthy range)
25.0 - 29.9	Overweight	Moderate risk of developing heart disease, high blood pressure, stroke, diabetes
30.0 - 34.9	Obese (Class I)	High risk of developing heart disease, high blood pressure, stroke, diabetes
35.0 - 39.9	Obese (Class II)	Very high risk of developing heart disease, high blood pressure, stroke, diabetes
40.0 and above	Obese (Class III)	Extremely high risk of developing heart disease, high blood pressure, stroke, diabetes

These categories are based on the WHO's recommendations and provide a general guideline for assessing body weight. Individual variations may exist, and other factors should be considered when evaluating health.

Limitations of BMI

While BMI is a useful screening tool, it has several limitations:

It doesn't distinguish between muscle mass and fat mass
It doesn't account for body composition differences between men and women
It may not be accurate for athletes or people with high muscle mass
It doesn't consider other health factors like waist circumference, blood pressure, or cholesterol levels

For a more comprehensive health assessment, consider consulting with a healthcare professional who can evaluate your body composition, waist-to-hip ratio, and other health indicators.

Frequently Asked Questions

What is a healthy BMI?

A BMI between 18.5 and 24.9 is considered normal weight by the WHO. This range is associated with a lower risk of developing health problems related to weight.

Is BMI accurate for all age groups?

BMI is generally accurate for adults, but it may not be appropriate for children or adolescents. Specialized growth charts are typically used for younger populations.

Can BMI be used to diagnose obesity?

While BMI can indicate a higher risk of obesity, it's not a definitive diagnosis. Other factors like waist circumference, body fat percentage, and overall health should also be considered.

How often should I calculate my BMI?

It's recommended to calculate your BMI regularly, especially if you're trying to maintain a healthy weight. However, don't focus solely on BMI - it's just one indicator of overall health.

What should I do if my BMI is in the overweight or obese category?

If your BMI falls in the overweight or obese category, consider consulting with a healthcare professional for personalized advice. They can help you develop a healthy eating plan and exercise routine tailored to your needs.