Remember to use negative values for owed balances and money paid to the account, positive values for balances in your favor and money withdrawn from the account. Also enter the interest rate per period , not per year . If you are making monthly payments and have an annual interest rate, divide the annual rate by 12.

Math Note: This business of dividing an interest rate by 12 is not mathematically correct, but since the banks use this procedure it is wise to do it also, otherwise your numbers will not agree with those of the bank. Thus, one period of an 8% annual rate is 8/12 and is entered as .666666.