BMI Calculator

How much should I weigh?

What's my BMI

Health risks from being overweight

These consequences are related to overweight and obese adults

Adults whose BMI is greater than 25 (overweight) or whose Body Mass Index is greater than 30 (obese) have a heightened risk for divers diseases and health conditions, including,:

Derivation

BMI Prime is simple way of defining a single figure that is not immedieately related to any other units of measurement, but which can quickly and easily rank a person into a category. :Eg:
  • BMI Prime < 0.74 = Underweight
  • BMI Prime > 0.74 and < 1.00 = Optimal weight.
  • BMI Prime > 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.
See wikipedia.org/wiki/Body_mass_index#Limitationsinfomation.