This calculator will show you how much interest you will end up paying if you make only the minimum required payment on your credit card bill. It will also tell you how many minimum payments you will make before your balance is paid off (up to a maximum of 600 payments).
 

Instructions: Somewhere in your credit card disclosure statement the card company will tell you something like "your minimum payment will be 2% of the balance or $10, whichever is higher. These are the figures you will enter in Column C and Column D respectively. “Leave the last three fields blank and hit the compute button.”