Multiply your bodyweight by 12. This is your BMR. Now, according to your level of activity, multiply 12 by
Lightly Active - 1.1-1.2
Moderately Active - 1.2-1.3
Highly Active - 1.3-1.4
Something along those lines. Lightly would be sitting around most of the day, some slight walking. Maybe a desk job, and walking around the supermarket to shop.
Moderately would be on your feet all day, maybe some form of exercise 3x a week.
Highly would be something like an athlete or construction worker. Heavy work all day long.
This is the amount of calories your body will be consuming daily. 500 above this daily will net you one pound a week. 500 below, as expected, will drop you a pound a week.