If you need to know how much your vehicle has cost for a particular journey then you need to work out what it's "CPM" is (Cost per mile). This handy app needs only two bits of information from you to work this out. Simply enter your vehicles documented "MPG" (Miles per gallon) in the first box then enter how much you are currently paying for one litre of fuel - hit the calculate button and hey presto your "CPM" (Cost per mile) will be shown. it will also inform you of your "MPL" (Miles per litre).