See your BMI on a graph

How much should I weigh?

BMI Calculator

Health risks from 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,:

Explanation

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
The BMI, also 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.

Do the sums

BMI is defined by the following formula
  • BMI = weight(kilograms) / height2 (metres2)         (Metric Units)
  • BMI = 703 . weight(pounds) / height2 (inches2)         (Imperial Units)

BMI limitations

BMI calculations do not differentiate between muscle mass and fat mass.
See wikipedia.org/wiki/Body_mass_index#Limitations for more information.