I'm sure Jaime will chime in and give good advice but if you have a simple interest loan on your car I believe the interest accrues each day.. so if you make a payment on the first day after your previous payment you will not pay half as much interest if you wait till when it is due. Basically a bigger chunk will go toward the principle and you will pay the loan off a LOT faster.. that is what I do with my credit union and I pay them off within a year. (making additional payments of course)