Credit utilization.

In plain English

Credit utilization is how much of your credit card limit you're using. If your card has a $10,000 limit and your balance is $3,000, your utilization is 30%. It's one of the biggest factors in your credit score, second only to whether you pay on time. The lower your utilization, the better your score, even if you pay the bill in full each month.

01Why it matters

Most people don't realize this is reported on the day the statement closes, not the day you pay. So even if you pay your bill in full every month, you can have high utilization on your credit report if your statement closes before you pay. That alone can drop a score by 30-50 points.

02The math, step by step

You have one credit card with a $5,000 limit. You spend $2,500 on it during the month. Your statement closes on the 25th. That's the day the $2,500 balance gets reported. Even if you pay the full $2,500 on the 26th, your credit report shows 50% utilization for that month. If you'd paid $2,000 of it before the 25th, your reported utilization would have been 10%, and your score would likely be higher.

Illustrative example. The amounts here are hypothetical, chosen to show how the math works, not real quoted rates or figures.

03What this is NOT