SimpleIFTA is an Android app that is easy to use. Simply start the app’s odometer at the first quarter of your trip, and again when you cross the state line, and when you end your trip. Enter fuel when you stop for fuel, you already entered the state when you crossed the line, so it’s already taken care of.
“Smart enough to know what states you can cross into when you go to enter the next! If you entered your starting state at the beginning of the quarter, from that point on only states that you can cross into will be offered as options when you enter a state line odometer reading. No need for scrolling through a long list of states, only the ones that are possible are there,” the app’s developer states.
The app only works in the lower 48 states and can be downloaded on Google Play.