Calorie wiggle room?

nonSinistral

I was just wondering what is generally considered an acceptable overage in calorie intake. I've changed my goals since I joined mfp and my daily calorie goal has gone from 1550 to 1490, so I am already in a stage of transition to lessening, but today is just one of those days when I had a snack or two more than usual. I think 100 or so calories over isn't too bad. Am I just fooling myself, or does everyone have that sort of wiggle room?