Find out your cal burn/day... should be lotsa calculators online... my favorite formula (for men):
A) weight in lbs x 11 = BMR
B) to add for activity, multiply BMR by
-under 30yo: 0.3 if sedentary, 0.4 if moderately active, 0.5 if very active (pretty much only every day cardio or lifting)
-30-40yo: .25, .35, .45
-40+ yo: .2, .3, .4
You can take intermediates if you want, eg a pretty active (but not a extremely) 25yo would could use .45
C) add BMR from A and activity from B.... that is about what you burn (you will have to adjust a lil based on results; everyone has slightly different metabolism/activity)
...to bulk natural, I add 700 cals to what I burn. To bulk on cycle, I will be adding another 1000 cals on top of that (prolly a quart of skim and a quarter jar of PB each day).