BMI Calculator

Calculate your Body Mass Index to see where you fall on the underweight-to-obese scale, plus your healthy weight range.

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What is BMI?

Body Mass Index (BMI) is a simple calculation using your height and weight to estimate body fat. The formula divides your weight in kilograms by the square of your height in meters.

BMI Categories

  • Underweight: BMI below 18.5
  • Normal weight: BMI 18.5 – 24.9
  • Overweight: BMI 25 – 29.9
  • Obese (Class I): BMI 30 – 34.9
  • Obese (Class II): BMI 35 – 39.9
  • Obese (Class III): BMI 40+

Limitations of BMI

BMI doesn't distinguish between muscle and fat mass. Athletes and muscular individuals may have a high BMI while being healthy. For a more complete picture, consider measuring your body fat percentage or checking your ideal body weight.

Frequently Asked Questions

What is a healthy BMI range?
A healthy BMI is between 18.5 and 24.9. Below 18.5 is considered underweight, 25-29.9 is overweight, and 30 or above is classified as obese. However, BMI does not distinguish between muscle and fat, so muscular individuals may have a high BMI while being healthy.
Is BMI accurate for athletes?
BMI is not accurate for athletes or muscular individuals because it cannot distinguish between muscle mass and fat mass. A bodybuilder with low body fat could be classified as overweight or obese by BMI alone. For these individuals, body fat percentage is a better metric.
How is BMI calculated?
BMI is calculated by dividing your weight in kilograms by the square of your height in meters: BMI = weight(kg) / height(m)². In imperial units, the formula is: BMI = (weight in pounds × 703) / (height in inches)².