Graph your BMI

What is a healthy bmi

BMI Calculator

Risks of being overweight

These dangers are associated with overweight and obese adults

Adults with a BMI of greater than 25 (overweight) or whose BMI is greater than 30 (obese) have an increased risk for a number of diseases and health conditions, including,:


Body Mass Index Prime is method of using the results of the BMI calculations to quickly and easily rank a person into a category. Eg:
  • BMI Prime less than 0.74 = Underweight.
  • BMI Prime greater than 0.74 and less than 1.00 = Optimal weight.
  • BMI Prime greater than 1 = Overweight
BMI, sometimes known as the Quetelet index, is a measure used to estimate a person's body shape based upon a person' weight and height. It originated in Belguim around the 1840's by Adolphe Quetelet. It is a simple calculation based on the individual's body weight divided by the square of their height.

The simple maths

Use the body mass formula to get your bmi
  • BMI = weight(kilograms) / height2 (metres2)         (Metric Units)
  • BMI = 703 . weight(pounds) / height2 (inches2)         (Imperial Units)

BMI limitations

BMI is proportional to the mass and inversely proportional to the square of the height. So, if all body dimensions double, and mass scales naturally with the cube of the height, then BMI doubles instead of remaining the same. This results in taller people having a reported BMI that is uncharacteristically high, compared to their actual body fat levels.