How do I determine the number of calories I need?

distinctlybeautiful

I'm not bulking yet but looking forward to it, and I figure this question is also relevant to maintaining/recomping, which I'm trying to do now.

Everything I've read says it's very difficult to determine how many calories are burned during strength workouts. So how do I know how much I should be eating on days when I lift? Right now I simply enter it under cardio exercises and rely on the calorie burn MFP gives me.

I've been eating at what I figure is maintenance, but I recently posted in the success stories that I was recomping successfully and got feedback that I must be in a deficit because I've actually lost about 12 pounds over a year (dropped 17 pounds of fat and gained 4.5 pounds of muscle!!). Now, I'm not too concerned about this right now because while maintenance has been my goal, I'm ok with that slow loss and that muscle gain. However, when it comes time to bulk, it seems that getting the number right will matter more. So I figured I'd ask now while I was thinking about it. Thanks!