BMI stands for Body Mass Index, and it is the main determinant for being obese or overweight in recent government guidelines.
The new system drops the old “ideal weight” concept and uses the relationship between your height and weight to calculate whether you are overweight or obese and therefore at higher risk of many diseases.
A BMI higher than 25 indicates that you are overweight, and 30 or higher denotes obesity.
If you are good with metrics, start by converting your weight and height to the metric system. Then take your weight in kilograms, and divide by your height in meters squared.