During every workout your body is burning up calories. Your weight, fitness level, intensity, workout duration, and even exercise type changes the amount of calories burned. A heart rate monitor HRM is the best way to figure out your caloric burn rate. (Many new gyms are actually putting in these monitors on their tread mills and putting the counter up on a screen). You need to feed your muscles so that is why you get those extra calories. Yes you should eat them. Do not go over them but they are added back into your daily caloric count because you are building a better body!
JesiF, thats an estimate of the calories that you burned doing the exercise, not calories consumed.