 your tractor payment is costing you 19.3 cents per mile. Drive 10,000 miles, though, and that same payment will cost you 18.5 cents per mile. This is one of your major fixed costs while paying off a truck loan. The difference in this example is only a fraction of a cent, which may seem like small change, but it ultimately amounts to $960 more annually on the bottom line. Because though fixed costs do not go down over time, you can reduce your cost per mile with more paid miles.