6 credit report score killers
Delinquencies are "huge influences" on the credit score, said Stephen Brobeck, executive director of the Consumer Federation of America. In fact, they make up 35 percent of your FICO score. If you see notations that bills have been paid 30, 60, 90, or 120 days late, "that's very damaging," he said.
The other factor that's important here: the timeline. How late was the payment, and how long ago did you make this mistake? The good news is that the more time that has passed since you made a late payment, the less it will affect your credit.