BMI stands for body mass index. Your BMI is a measurement of your body weight based on your height and weight. While your BMI doesn't actually measure your percentage of body fat, it can be a useful way of estimating a healthy body weight based on your height. Because it's an easy figure to calculate it's widely used as an indicator to identify a person's optimal weight based upon their height. Your BMI number will tell you if you are underweight, of normal weight, or overweight or even obese. While BMI as a mesurement can be helpful, due to a wide variety of body types and the distribution of muscle and bone mass BMI isn't a perfect measurement of a persons health or weight.

Body Mass Index or BMI is widely used and can be helpful, however many criticize using it as a measure of health or fitness for several reasons. BMI ignores body composition, it only considers weight and height, it neglects factors like muscle mass, bone desntiy and fat distribution. This can cause individuals with high muscle mass ie athletes and bodybuilders to be classified as obese while overlooking health risks in those with "normal" BMI but high visceral fat. BMI also doesn't account for individual differences and ignores things like sex, ethnicity and age. Some ethnicities tend to carry more muscel or have different fat distribution patterns  

If you're wanting to find out your BMI you can use the handy BMI Calculator above. If you'd like to calculate it yourself it's a simple formula that takes into account your height and weight. Here's a step by step guide...

1. Square your height in inches
2. Multiply your weight in pounds by 703
3. Divide the result from step 2 by the squared height in inches

The resulting value is your BMI.

No, BMI is calculated exactly the same for men and women, however the interpretation of the BMI values may differ when looking at men and women. Men and Women generally have different body compositions, for example women tend to have a higher percentage of body fat than men with the same BMI. As a result of this the same BMI value may represent different body compositions in men and women.

The World Health Organization (WHO) provides some guidance on BMI. They state that a BMI of less than 18.5 is considered underweight, 18.5 to 24.9 is considered normal weight, 25 to 29.9 is considered overweight and a BMI of 30+ is considered obese.

IIt's important to note that while BMI can be a useful screening tool it does have limitations. BMI does not directly measure body fat percentage and it doesn't account for variations in muscle mass, bone density or fat distribution, therefore individuals with the same BMI may have different body compositions.