How to Calculate Gas Mileage

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With the cost of gasoline fluctuating between expensive and astronomical, many drivers are very concerned about the gas mileage their car is getting. It is quite simple to calculate your vehicle’s average gas mileage using these simple steps.

How To Proceed

  1. 1

    Find out the capacity of your gas vehicle’s gas tank. This information can be found in your vehicle’s owner’s manual. Most vehicles gas tank capacity ranges from ten gallons for small compact cars to forty gallons for large trucks or SUVs.

  2. 2

    Fill it up. Fill your vehicle’s gas tank to full capacity. Most gas pumps have a mechanism that will stop the flow of gasoline when the tank is full. When you turn your car on, make sure that the gas tank gauge indicates that your tank is completely full.

  3. 3

    When you look on the gas pump to see how much money you need to pay for your gas, notice the reading of the amount of gallons you purchased. There should be an exact reading of how many gallons you bought to the hundredth of a gallon. This number should be close to the total gas tank capacity listed in your owner’s manual. Make a note of this amount. If the gas pump you used to fill up does not have this function, you can divide the total amount of your gasoline purchase by the price per gallon.

  4. 4

    Set your trip odometer. This is typically located on your dash board and is set by pushing a button located somewhere around the speedometer or RPM gauge. Make sure to complete this step as soon as you fill your tank with gas and before you begin to drive.

  5. 5

    Drive your car as you normally would.

  6. 6

    Drive your vehicle until the gas light comes on to indicate to you that you need to refill your tank. At this point, take note of your odometer reading for the trip you set when you filled your tank.

  7. 7

    Time for some math. Divide the total number of miles you drove on this tank of gas by the number of gallons of gas that you purchased when you filled your vehicle’s gas tank. The solution to this problem will be the average miles per gallon of gas that your vehicle gets.

Many drivers use particular driving strategies to improve their vehicle’s gas mileage such as slower acceleration and lower speeds. Knowing your vehicle’s average miles per gallon rating will also allow you to budget your gas expenses more accurately.