Fuel Mileage Calculator to Calculate and Compare Fuel Economy

Fuel Mileage Calculator Sign

This calculator will calculate miles per gallon (MPG), kilometers per liter, or liters per 100 kilometers and associated daily, monthly, and annual gas expenses for your car, truck, RV, or bike.

Plus it also gives you the ability to compare fuel costs with other fuel economy ratings to see how much you could save by switching to a vehicle with a better rating.

And, unlike other online gas mileage calculators, the calculator will also figure your lifetime gas expenses based on your vehicle's fuel efficiency rating and on the distance you drive your vehicle each year.

You'll be amazed not only by how gas expenses can pile up over your lifetime but also by what a big difference it can make by switching to a vehicle that gets just a few more miles per gallon or kilometers per liter.

If you would like to estimate the cost per mile that includes all costs associated to buying and owning a vehicle (gas expense plus tax, license, finance charges, depreciation, insurance, maintenance, repairs, etc.), be sure to visit the Car Buying Calculator.

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Fuel Mileage Calculator

Calculate fuel economy for your car, truck, or bike, and get a forecast of your daily, monthly, annual, and lifetime gasoline costs.

Special Instructions

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Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None

Fuel and distance type:

Select the calculation that reflects your country's fuel and distance units.


Distance entry method:

Select your preferred distance entry method.

Beg odomBeg odometerBeginning odometer readingBeginning odometer reading:

Beginning odometer reading:

If you selected "Odometer readings" as the distance method, enter the beginning odometer reading on this line.

End odomEnd odometerEnding odometer readingEnding odometer reading:

Ending odometer reading:

If you selected "Odometer readings" as the distance method, enter the ending odometer reading on this line. The numbered entered must be greater than the beginning reading.


Trip distance:

If you selected "Trip distance" as the distance method, enter the number of trip units (miles or kilometers) traveled between fuel fills. Otherwise, this field will be disabled and filled in for you if you opted to enter odometer readings.

# gallons# of gallonsNumber of gallons this fillNumber of gallons pumped this fill:

Number of gallons pumped this fill:

Enter the number of units (gallons or liters) of gas it took to refill the gas tank on your car, truck, or two wheeler. Be sure to include the decimal portion of the unit meter on the gas pump.

Gas pricePrice/gallonPrice per gallon of gasPrice of one gallon of gasoline:

Price of one unit of gasoline:

Enter the current price of one unit of gasoline (or diesel fuel), but without the dollar sign. The calculator will use this figure to forecast your periodic fuel expenses.

Avg milesAverage milesAverage milesAverage miles:

Average number of distance units driven per period:

Select the distance time period for which you know the average number of distance units you drive your vehicle. Then enter the average number of distance units for the selected time period. The calculator will use this figure to forecast your periodic fuel expenditures.

Life yearsLife yearsYears to calculate lifetime costsNumber of years to calculate lifetime costs:

Number of years to calculate lifetime costs:

Enter the number of years you would like the fuel efficiency calculator to figure lifetime fuel expenses for.

Invest ROIInvest ROIExpected return on investmentsExpected percent return on investments:

Expected percent return on investments:

Enter the annual percentage return you would expect to earn on your investments. Enter as a percentage, but without the percent sign (for .06 or 6%, enter 6). The calculator will use this figure to estimate what would happen if you invested the fuel expense savings realized by switching to a vehicle with better fuel efficiency.

MPG:Miles per gallon:Miles per gallon:Miles per gallon:

Miles per gallon:

Based on your beginning and ending odometer readings (or trip distance) and the number of units pumped, this is your vehicle's calculated fuel economy.

Gas Mileage Comparison Calculator

Expense and comparison chart:

This chart will display the calculated daily, monthly, annual, and lifetime fuel expenses based on your car's fuel economy and on the entered average distance you drive the car per selected period.

To see how much you can save by switching to a car that gets better fuel economy, select a comparison fuel economy from the menu located at the top of the 2nd column. The chart will automatically recalculate each time you make a new selection.

Now MPGNow MPGCurrent MPGCurrent MPGComp MPGComp MPGCompare MPGCompare MPGSaveSaveSavingsSavings
MPG:MPG:Miles per gallon:Miles per gallon:
Day:Daily:Daily expense:Daily fuel expense:
Mon:Month:Monthly expense:Monthly fuel expense:
Year:Year:Annual expense:Annual fuel expense:
Life:Lifetime:Lifetime expense:Lifetime fuel expense:

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

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Help and Tools


Gas expense factors other than the price of gas, and how to calculate fuel economy.

How to Calculate Gas Mileage

Before using the fuel mileage calculator, you will first need to log the data you will need to enter into the calculator (or that you will need to calculate MPG) as detailed below:

  1. The next time you visit the gas station to refill your car's gas tank (the less fuel you have in your tank, the better), write down the odometer reading (beginning reading).
  2. On your return trip to the gas station to refill your car's gas tank, write down the odometer reading (ending reading) and the number of gallons or liters it took to refill the tank.

If you want to calculate the fuel economy yourself, here is the formula:

Fuel economy =
  ending odometer reading
  - beginning odometer reading
÷ number of gallons or liters to refill tank

Of course, now that you have discovered this page you don't need to know how to calculate gas mileage. All you need to do is plug in the numbers and click the "Calculate Fuel Economy" button.

How to Calculate Price of Fuel

If you know the number of units pumped and the total price of the fill, this mini calculator will tell you the price per unit of fuel.

Fuel Price Calculator
Units pumped (#):
Total cost of fill ($):
Price per unit:$2.29
Fuel price = fill cost / units pumped
Fuel price = 53.36 / 23.3
Fuel price = 2.29

The Price of Gas is NOT the Reason for High Gas Expenses

I always have to chuckle when I overhear someone complaining about the price of gas, especially when they are:

  • leaning over the hood of their idling SUV that has a low tire on the right front ...
  • having just stopped by the coffee shop for a $3, 12-ounce cup of designer coffee ...
  • while on their way home from fighting stop-and-go rush hour traffic ...
  • and are now parked in an out-of-the-way grocery store to pick up a loaf of bread.

First off, why aren't they complaining about the $32-per-gallon cup of designer coffee they are holding in their hands?!

Secondly, if they are so concerned about the cost of gasoline, why are they driving a gas guzzling SUV?

Thirdly, why didn't they buy more bread the last time they made a special trip to the grocery store?

Why don't they take a minute to air up that low tire?

And finally, why have they chosen to work at a job that forces them to drive during the most fuel-sucking time of the day?

My point is, the price of gasoline is only a tiny part of the gasoline expense equation. More important factors include:

  • The MPG rating of the vehicle you drive.
  • The conditions under which you drive your vehicle.
  • The planning needed to avoid unnecessary trips.
  • And having the freedom to choose when to commute and how (walk, bike, carpool, or public transportation).

However, if you wish to shop for vehicles with the best fuel economies, I encourage you to visit the EPA's list of the Best and Worst Fuel Economy Vehicles.

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.