Fuel Capacity Rating

• The listed volume capacity of a fuel tank is based on an average volume that can be put into a tank after multiple fill-ups. This rating may include only the usable portion of a vehicle's fuel tank or it may include both the usable and unusable portions. The usable portion of the tank is that which can be delivered through the tank's filler pipe into the tank when the vehicle is level. The unusable portion is that at the bottom of the tank out of the reach of the fuel pump.
  
  

Average Fuel Capacity

• For standard, mid-size sedans, fuel tank capacities range from 16 to 19 gallons. As previously mentioned, capacity can vary as much as 3 percent of the rated capacity.
  
  

Indicated Volume

• The fuel indicator on the dashboard of the vehicle displays an approximate volume percentage of the fuel remaining in the tank. This indication can be affected and may be misleading if the vehicle is not on level ground, such as when it is on a hill or traveling around a curve.
  
  Some newer vehicles have a feature typically called a "Distance to Empty". This takes the average miles per gallon of the vehicle and calculates, based on the usable fuel remaining in the tank, how far the vehicle could travel on that fuel. As the indicated volume in a tank can be skewed by the vehicle not being on level ground, etc., the "Distance to Empty" feature should not be considered 100 percent accurate.