Ok for starters, A good way to determine how many calories to eliminate is to do simple math regarding a lbs of fat.

1lbs of fat = 3500kcal.
2lbs of fat = 7000kcal

Generically, you would subtract 500 calories a day. What I advise is multiplying 4 by your LBM in lbs. But you need to get a good grasp on your bf% as close as you possibly can. Any big chain gym will have a method of measuring body fat.

A few other ways would involve doing it yourself.

Tape measure method (US Navy)
BIA - Bioelectrical Impedance scales
Calipers