How To Figure Gas Mileage

Learning how to figure gas mileage is a fairly simple procedure. If your car has an adjustable odometer, figuring your gas mileage can be accomplished each time you fill up your gas tank. The key to getting an accurate picture of your gas mileage is consistency. You have to be consistent in the brand of gasoline you use, the type of gas, the station you go to, and  your driving routine.

1. Drive to a gas station you would normally go to. Turn off your engine and set your odometer to zero. There is usually a knob located under the odometer. Push the knob in and set it zero.  You might have to pull it out or turn it right or left on some cars. If your car does not have an adjustable odometer, write down the mileage shown on the fixed odometer and store it for future reference.
   
2. Set the gas pump lever on the handle to auto-stop so it will automatically stop filling. When it shuts off, do not pump any more gas and remove the gas nozzle.
3. Drive  your car as you normally would without making any changes to your driving habits.  Do not drive slower to save gas and avoid checking your mileage during hot months when you are inclined to use your air conditioner. Air conditioners take energy from your engine and can consume more gas than normal, giving you an inaccurate picture of your gas mileage.
4. Wait until you your gas tank is half-empty before filling up again.  Always use the same type of gas so that your mileage will reflect as many different driving conditions as possible.
5. Go to a gas station and fill-up your tank as in Step 2. Try to use the same gas station and gas pump as you did before. The auto-stop device, and when it shuts off, can differ from each pump.
6. Check the number of gallons indicated on the pump when it shuts off and write it down.  Check your odometer and write down the number of miles shown.
7. Divide the odometer mileage by the number of gallons pumped. That figure should show you how many miles per gallon your car is getting. If you have a fixed odometer, subtract the number originally written down from the number now showing. The difference will be the mileage driven.
8. Consider as an example, driving 200 miles and filling up requires 10 gallons.  200 divided by 10 equals 20, which is your miles per gallon.
9. Repeat the process of filling up and recording your mileage at least three times.  This will insure greater accuracy that will cover every driving condition over a period of time.
10. Do not drive off before setting your odometer back to zero or writing down you present mileage. Remember to  keep a record of each fill-up for comparison now that you know how to figure gas mileage.