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BMI Calculator

Calculate your Body Mass Index (BMI) and find your healthy weight range based on your height.

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About BMI

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared.

BMI Categories for Adults:

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

For Children and Teens (2-19 years):

BMI is calculated the same way, but the interpretation is different. Results are compared to typical values for other children of the same age and sex, using percentiles:

  • Underweight: Less than the 5th percentile
  • Healthy weight: 5th to 84th percentile
  • Overweight: 85th to 94th percentile
  • Obesity: 95th percentile or greater

Limitations of BMI:

BMI is a useful screening tool, but it has limitations. It doesn't distinguish between muscle and fat, nor does it account for factors like age, sex, ethnicity, or muscle mass. Athletes and muscular individuals may have a high BMI without excess fat.

Understanding Your BMI

BMI provides a simple numeric measure of your weight relative to height. It was developed in the 19th century by Belgian mathematician Adolphe Quetelet and is widely used as a screening tool to categorize weight status.

Why BMI Matters

Research has shown that BMI correlates with direct measures of body fat and with various health risks. Higher BMIs are associated with increased risk for conditions like:

  • Heart disease and stroke
  • Type 2 diabetes
  • High blood pressure
  • Certain types of cancer
  • Sleep apnea and breathing problems
  • Osteoarthritis

Beyond BMI

While BMI is useful for population studies and general screening, it doesn't tell the complete story about your health. Other factors to consider include:

  • Body composition: The ratio of fat to muscle in your body
  • Fat distribution: Where fat is stored on your body (abdominal fat carries higher health risks)
  • Waist circumference: A measurement of abdominal fat
  • Lifestyle factors: Diet quality, physical activity, sleep, and stress
  • Family history: Genetic predisposition to certain conditions

For a more comprehensive assessment of your health status, consider using our other calculators like the Body Fat Calculator or ABSI Calculator, and consult with healthcare professionals.