See your BMI on a chart

Chart your BMI against the national average

What's my BMI

Health risks from being overweight

These dangers are identified with overweight and obese adults

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

Details

Devised all the way back in way back in 1830, BMI is a single figure used to as a way of measuring a person's body shape. Put simply, it is calculated by dividing the body's weight by the square of their height. Eg: Kilograms: weight, divided by Metres (Meters): height. 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

How Body Mass Index is worked out
  • 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.