Body Mass Index (BMI) is used to place a person into one of several categories according to their height and weight. A person can be classified as very severely underweight, severely underweight, underweight, healthy, overweight, moderately obese, severely obese or very severely obese.
While it can be a useful tool, it's worth noting that BMI has come under criticism for several reasons:
- It does not cater for the fact that body dimensions tend to be different for taller and shorter people and incorrectly works on the basis that mass is inversely proportional to the square of height. Because of this taller people may find themselves placed into a higher BMI category than would be expected.
- It doesn't take into account the ratio of lean body tissue to fat. As a result those with muscular builds may find themselves placed in the wrong categeory.
- It can shift the focus from a healthy lifestyle to a focus on weight, which it is argued is a less important - and possibly unhealthy - approach.
- The boundaries are somewhat arbitrary, even differing between countries.
- It's been argued that while BMI is useful for considering trends in populations, it is much less useful for individuals.
Given its flaws it's probably best to use BMI as a guide - along with other available information - when assessing your healthy weight.
To use the tool simply enter your height and weight and hit "Calculate"