How to Calculate MPG

MPG in short, stands for Miles Per Gallon. Fuel efficiency is becoming a more serious factor as gas prices continue to rise. Once the MPG is figured out, many useful things can be done, such as calculating how much a rise in gas will affect your budget or how a car with better MPG will reduce the monthly costs.

The only things needed to calculate an MPG are paper, pen and calculator. Here the simple steps to calculate MPG or Miles Per Gallon:


  1. A pen and paper should be made ready when you are at the pump. Now start filling the tank.
  2. Collect the information. Record the mileage, in order, the current odometer reading and the amount of gallons filled. This process has to be repeated few times when you go to the gas station for getting good average.
  3. Take a calculator, subtract the second odometer reading from the first reading and the result will show the amount of miles that were travelled from the last time you went to the gas station. This number would be used in the next step.

Calculate MPG

  1. Now when the miles travelled have been calculated, this has to be simply divided by the amount of gallons that was used to refill the tank. The calculated result is the car’s average MPG. As mentioned above, these steps should be calculated a couple of times to get a good average.


  • To determine the effect on your budget due to a change in gas prices, take the number of miles expected to drive in a week or month or even year. This is to be divided by the MPG. Then, the answer is to be multiplied by the price of gas per gallon. By just calculating various prices, it will be determined how much more or less you will pay per week or month or year.
  • The MPG can be used to experiment with ways for increasing fuel efficiency. For instance, if a car is driven at an average speed of 70 mph, then the MPG can calculated and after that, try to drive at 55 mph and calculate the MPG again. It will be probably seen going up.
  • The higher the MPG will be, the more efficient the car will be, and it will be fueled at a cheaper rate.
  • In case, you want to calculate the average cost per gallon, and then just divide the total money spent by the number of gallons filled in the car.


  • The mileage varies with different driving patterns, less acceleration and braking will result in better mileage. Higher mileage will be seen when taking long trips.
  • Don’t talk on the cell phone while filling gas.