Body mass index (BMI) is simply a relationship between weight and height. For the vast majority of people, BMI will give a good measure of whether the weight is normal or needs to change.
Some populations such as bodybuilders will have a higher BMI because of muscle mass. This tool cannot distinguish between muscle and fat so it is up to you to decide whether you have excess fat or are muscular.
| Your BMI | Weight Category |
| 18.5 and Under | Underweight |
| 18.6-24.9 | Normal |
| 25-29.9 | Overweight |
| 30-34.9 | Obese Class 1 |
| 35-39.9 | Obese Class 2 |
| 40 and Over | Obese Class 3 |