When you're paying, you know how much you're paying, right?

No.

And when it comes to credit cards, when something goes wrong, like a late payment, would you know how long that will hurt your credit?

Nope.

A survey out from TrueCredit.com, a unit of TransUnion, says we're really not well informed at all.

The poll by Zogby International was an online survey of 2,557 adults taken earlier this month. It showed:

Most people have no idea what's a normal interest rate on a credit card. Fully 84% said they don't know the current average interest rate on a credit card. It's 13.6 percent, Bankrate.com reports.

More than half (or 54%) don't know how long a late payment will remain on their credit report. The answer is seven years.

Oh, and, 90 percent believe a credit score is included on a credit report. It isn't. Generally, you have to pay to get it in a separate report, while you can get a credit report for free once a year.

Dismal as the report is, it's a giant flashing arrow to the lesson of the day: Get your credit card facts straight. A little bit of knowledge will help you select the best deal out there.