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BMI Calculator

Calculate your Body Mass Index (BMI) to assess your weight relative to your height. Supports both metric and imperial units.

cm
kg

BMI Categories

Underweight
< 18.5
Normal weight
18.5 - 24.9
Overweight
25 - 29.9
Obese (Class I)
30 - 34.9
Obese (Class II)
35 - 39.9
Obese (Class III)
≥ 40

What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight. It applies to adult men and women and is commonly used to screen for weight categories that may lead to health problems.

BMI Formula

BMI is calculated using the following formulas:

  • Metric: BMI = weight (kg) / height (m)²
  • Imperial: BMI = (weight (lbs) / height (in)²) × 703

Limitations

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

  • Does not measure body fat directly
  • May overestimate body fat in athletes and muscular people
  • May underestimate body fat in older adults
  • Does not account for muscle mass, bone density, or fat distribution

When to Consult a Doctor

BMI is just one indicator of health. If you have concerns about your weight or health, consult a healthcare professional for a complete assessment that includes other factors like waist circumference, blood pressure, and blood sugar levels.