Hey this is Dave, now question is, how much paint do you need?
This Regal select for instance, 400 to 450 square feet. Okay so you could measure your room, you know 10 feet high, overestimate, 40 feet around, and your going to get your 400 square feet. However, your walls might be very dry, it will suck in the paint. You might need a little bit more than that.
Now, were not incidentally pre-priming the wall with a specific primer because this is a primer, paint and primer in one. OK. A high end contractor might be fully priming a wall, if he had skin coated. But if you want to get the job done, and your using a modern water based self priming paint, which most of them are now, your not going to be pre-priming the wall. Your going to be putting the paint straight on. So sometimes this 400 square feet is an underestimation. You might as well consider a normal room, a bedroom from medium size to slightly larger, two gallons of paint. And again on your walls, matte, eggshell.
A ceiling is usually going to be the same color throughout an apartment. So you might consider three gallons of a flat paint for your ceiling to cover a normal one bedroom apartment.
For your semi-gloss, one gallon might be enough to do all your doors, baseboard and trim in a one bedroom apartment. So we have one gallon for your trim, woodwork, baseboard. And we have three gallons for your ceiling, and two gallons for a normal sized room.
An entryway or a hallway, you might get away with one gallon. A large living room, dining room area factor in possibly three gallons. That should get you started in paint quantities, you don't want to have to make extra trips. Get it all at once.