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Imperial (lbs, in)

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Height cm

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Underweight
< 18.5 Normal
18.5 - 24.9 Overweight
25 - 29.9 Obese
≥ 30

About BMI

Body Mass Index (BMI) is a measure of body fat based on height and weight. It is a simple screening tool, but does not directly measure body fat.

Category	BMI Range
Underweight	Below 18.5
Normal weight	18.5 - 24.9
Overweight	25 - 29.9
Obesity	30 and above

Understanding Body Mass Index (BMI)

Body Mass Index (BMI) is a widely used screening tool to categorize individuals based on their body weight relative to their height. While it doesn't directly measure body fat, it provides a reliable indicator of body fatness for most people.

How BMI is Calculated

The formula for BMI is weight in kilograms divided by the square of height in meters (kg/m²). For imperial measurements, the formula is (weight in pounds / (height in inches)²) x 703.

BMI Categories

The World Health Organization (WHO) has established standard BMI categories:

Underweight: BMI less than 18.5
Normal weight: BMI between 18.5 and 24.9
Overweight: BMI between 25 and 29.9
Obesity: BMI of 30 or greater

Limitations of BMI

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

It may overestimate body fat in athletes and others with muscular builds
It may underestimate body fat in older persons and others who have lost muscle mass
It doesn't account for distribution of body fat
It may not be accurate for certain ethnic groups

For a more comprehensive health assessment, consult with a healthcare provider who can consider additional factors like waist circumference, diet, physical activity, and family history.

Frequently Asked Questions

What is a healthy BMI?

A healthy BMI typically falls between 18.5 and 24.9. This range is associated with the lowest risk of health problems.

Is BMI accurate for everyone?

BMI is a useful screening tool but may not be accurate for athletes with high muscle mass, pregnant women, the elderly, or certain ethnic groups.

How often should I check my BMI?

For most adults, checking BMI once every few months is sufficient unless you're actively trying to change your weight.

Can children use this BMI calculator?

This calculator is designed for adults. Children and teens require age and sex-specific BMI percentiles for accurate assessment.

What should I do if my BMI is outside the normal range?

Consult with a healthcare provider for personalized advice. They can help determine if your weight poses health risks and recommend appropriate steps.