What is BMR
Your body has a rate at which it burns calories. This is called your Base Metabolic Rate (BMR). Your BMR is affected by the amount of regular excercise that you perform. Regular exercise will increase your BMR. This means that even when you are not exercising you will be burning more calories.
If your goal is weight loss, this BMR calculator is a handy tool that helps you determine how much you need to reduce your daily caloric intake by to hit your target weight. For example, 1 lbs = 3500 calories so if you wanted to lose 1 lbs a week and your BMR was 2500 cal/day you would reduce your daily intake to 2000 cal/day (500 cal/day X 7 days = 3500 cal).