calories burned

celewis2011

How accurate is the calories burned this site gives you when you enter in your daily exercise. I don't have one of those arm counters, and I have been putting in my exercise but not counting it on my total calories that i ate for the day , so today i worked out 45 mins said i burned 711 calories , my total food intake was 1152 - 711 = 441 . i still count it as i ate 1152 total for the day and don't think of calories burned.