I see from your topics that this is about credit card bills. If you pay your bill in full every month, you are not (or shouldn’t be) charged any interest. It is not until you carry a balance that you start to pay the credit card company interest on your purchases. If you are carrying a balance, you still need to make the minimum payment on time or you will be charged a late fee. Further, you need to pay off as much as you can or you are charged a finance fee (ie, interest) on whatever you did not pay off fully the first time. However, if you have a long standing balance that you are trying to pay down, I believe paying the bill twice a month is meant to be paying above the minimum payment, above the new balance added for the second payment. This is a means of paying your card down faster. I suspect it is especially helpful for those who get paid every other week or weekly.