BMI Calculator: Easily Calculate Your Body Mass Index

BMI Calculation Tool

I developed and made available this BMI calculator (Body Mass Index) to allow you to quickly calculate your BMI based on your weight and height.
This simple and free tool helps you get a first indication of your body composition, according to standards defined by the World Health Organization (WHO).

With this BMI calculator, you can:

• calculate your BMI in seconds,
• know your body composition category,
• better understand your situation in relation to health recommendations.

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What is Body Mass Index (BMI)?

Body Mass Index, also called BMI, is an indicator used to evaluate the body composition of an adult.
It relates weight and height to obtain a numerical value that classifies a person into categories such as underweight, normal weight, overweight, or obesity.

BMI Calculation Formula

The formula to calculate BMI is:

BMI = weight (kg) / height² (m)

The unit of BMI is kg/m².

This indicator is widely used in medical and epidemiological contexts because it allows a quick and standardized assessment of body composition across the general population.

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Why Calculate Your BMI?

The World Health Organization (WHO) defined BMI as a reference indicator to evaluate risks related to overweight and obesity in adults.

Calculating your BMI allows you to:

• identify potential health risks,
• monitor changes in your weight over time,
• adjust your lifestyle (nutrition, physical activity),
• get a first indication before consulting a healthcare professional.

BMI results allow you to determine if a person falls into one of the following categories:

• underweight,
• normal weight,
• overweight,
• moderate obesity,
• severe obesity,
• very severe obesity.

Practical Example

A person weighing 100 kg:

• measuring 1.60 m would be classified as severely obese,
• measuring 2.05 m would have a normal body composition.

This shows the importance of height in BMI calculation.

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Presentation of the BMI Calculator

This online BMI calculator works with two input fields:

• height (in centimeters),
• weight (in kilograms).

Once the data is entered, the tool displays:

• the numerical BMI value,
• the corresponding body composition category,
• a summary table of BMI categories with example values.

The tool is intentionally simple, fast, and accessible to everyone.
No additional information is required to get a result.

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BMI Categories and Interpretation

BMI results provide an indication, but they must be interpreted carefully.

For example, a person measuring 1.70 m and weighing 72 kg is considered to have a normal body composition.
At 73 kg, they will not automatically be classified as overweight. Thresholds are gradual and should not be interpreted rigidly.

Limitations of BMI

BMI has several important limitations:

• it does not distinguish between fat mass, muscle mass, and bone mass,
• it may overestimate overweight in very muscular people,
• it may underestimate risks in individuals with low muscle mass.

For precise body composition measurements, medical examinations are required, such as:

• DEXA (medical reference),
• plethysmography,
• specialized imaging tests.

A bioelectrical impedance scale can also provide an estimate of fat, muscle, and bone mass, although these results remain approximate.

BMI therefore has limitations for athletes, very muscular people, or those with unusual bone structure.
It is primarily recommended to feel good in your body, practice regular physical activity, and adopt a healthy lifestyle rather than aiming for a strict BMI target.

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Frequently Asked Questions (BMI FAQ)

What is a normal BMI?

A normal BMI generally ranges from 18.5 to 24.9 in adults, according to WHO recommendations.

Is BMI reliable for athletes?

BMI can be unreliable for athletes, as increased muscle mass raises weight without reflecting excess fat.

Is BMI applicable to children?

No, BMI for children depends on age and sex. Specific growth charts are used.

Does BMI measure body fat?

No, BMI does not directly measure body fat. It is a general indicator based solely on weight and height.

How often should I calculate my BMI?

It is recommended to calculate your BMI periodically, especially when there is a change in weight or lifestyle.

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Conclusion

This BMI calculator allows you to quickly obtain an estimate of your body mass index using a simple and recognized mathematical formula.
It is intended for the general population and serves as a practical tracking tool without replacing professional medical advice.

For a complete assessment of your health, BMI should be interpreted in the context of your body type, activity level, and overall well-being.