I am trying to come up with the equation which will give me the total interest to be paid on something given a fixed interest rate with a fixed payment for a given period of time. The interest is applied to the remaining amount each month, after deducting any payments made.
I know how to work out the resulting total interest one month at a time, but I am unsure what the form of the equation would be given all of the known variables:
Fixed Monthly Payment
Fixed Interest Rate (% of Remaining)
Number of Months
= Total Interest