Multiply your bodyweight in lbs by 12 or 13 for a rough estimate. Variables like your age and metabolism, sex, lean body weight vs fat, activity level, insulin sensitivity, etc, will all play a part. No one here can say for sure what your caloric requirement is, and it will change from day to day based on lots of factors.
The foods you choose will make as much difference as the calories you consume. 2500 calories of sugar will make you lose muscle and gain fat, while a balanced 2500 calories could make you gain muscle and lose fat.
