Crack the credit card code

NEW YORK (CNNMoney.com) -- Your credit card interest rate could shoot past 30 percent, even if you have good credit.

Credit card issuers are tightening the reins, and it's consumers who are feeling the pain. Here's what you can do about skyrocketing interest rates.

This isn't a new trend. Credit card companies can raise your rate at any time for any reason - even if the economy is sour.

But credit card issuers are jacking interest rates up to 30 percent or higher for people with good credit, simply because their payments were late by a day.

If you've bounced a check, gone over your credit card limit, or missed a payment, default rates may be as high as 32.24 percent, according to a recent survey by Consumer Action.

Remember, the due date is a hard deadline. To protect yourself, you need to know when your credit card reports a late payment.

In some cases, you're one day past the due date, and you can be socked with default interest rates and late fees. In other cases, it can take several cycles before your late payment is noted according to John Ulzheimer of Credit.com.

Let's start with the annual percentage rate. We refer to this often as the APR. This is the yearly percentage rate charged when there is a balance on the card. This rate is applied each month that an outstanding balance is present.

Since the Fed has been on an interest-rate cutting mode, interest rates on variable interest rate cards are moving down.

But don't be surprised if some credit cards put a floor on how low their interest rates can go, says Linda Sherry of Consumer Action. This happened before during 2000.

You should look for the phrase "no lower than" when it comes to your APR. This may start appearing as early as mid-year, according to Sherry.

First, call the credit card company and ask if you can get your rate changed back to the original rate. If you've been a good customer, this could work.

If you are denied, make sure to ask if you would be able to get your original rate back if you make on-time payments for the next six months.

"Companies don't do a good job of advertising what is available," according to Sherry.

You can also ask the credit card company to freeze your rate below the default rate while you pay off the balance. Some cards will let you do that, but typically you won't be able to use that card for any more purchases.

And of course, if you're in the market for a new card, check out what other people are saying about it. Here are some Web sites: ripoffreport.com and cardratings.com.