An exclusive feature of GasMilesCalc allows the user to instantly display the total fuel cost for driving a given numbers of miles after the car mileage and the cost of fuel in dollars per gallon have been entered. The user can enter new values for total cost in dollars, distance in miles, mileage in miles per gallon and cost of fuel in dollars per gallon without having to re-enter all four values. This allows the user to instantly see the effect of changing one value. 5300 distance values betwenn 72 major US cities, 9 Canadian cities and 9 major US National parks are pre-programmed into the calculator. GasMilesCalc can be used as a standard decimal calculator with 9 memories for general problem solving.