Well, I'm not 100% sure. I am just starting to use a free internet software to help figure out my caloric intake. I haven't been perfect in entering everything, but I generally get at least 95% in. I've been averaging between the mid 3000 calories to just over 4000 calories.
I am 6 foot, 300 lbs. right now. My biggest problem with calories is the breakdown of them, between protein, fat, and carbs. My fat calories tend to be higher then they should be, figuring 55% of my calories from carbs, 25% from proteins, and 20% from total fat. I got these numbers from the suggested percentages by the software, but adjusted them as they had 55%, 15%, and 30% respectively.