A vehicle fuel mileage determining system includes a fuel consumption measuring device, a distance measuring device, a display configured to display fuel mileage data and a controller. The controller is coupled to the fuel consumption measuring device, the distance measuring device and the display. The controller is configured to calculate fuel mileage data using baseline data, data from the fuel consumption measuring device and data from the distance measuring device. The controller further shows the fuel mileage data calculated on the display. The controller is further configured to determine the baseline data as follows: in response to a reset condition being detected, the controller defines the baseline data as being equal to initial factory settings; and in response to the reset condition not being detected, the controller defines the baseline data as being equal to previously determined fuel and distance data.