Your BMR is the amount of calories your body requires just to perform its daily life sustaining functions.
Then, by using, the Harris Benedict Equation to calculate your total energy based on your activity level, as follows:
If you want to lose weight then you have to focus on less intake from your daily-recommended calories.
In order to lose 1 pound of fat each week, you must have a deficit of 3,500 calories over the course of a week. Cutting out about 500 calories each day will result in a 3,500 calories deficit over the course of the entire week.