What Is Good Gas Mileage and How to calculate it?

When determining what is good gas mileage, there are several factors to take into account. Look at the type of vehicle, fuel octane, and type of fuel. Hybrid and electric vehicles attain the best fuel economy, although numerous gas-powered vehicles get more than 30 miles per gallon (mpg).

What Is Good Gas Mileage?

Gas mileage is determined by the number of miles a vehicle can go on one gallon of gas. Hence the term “miles per gallon (mpg).” The higher the mpg rating, the better or more efficient a car is, and the lower the mpg rating, the worse it is.

Attaining good gas mileage means that you consume less gas for a larger distance per mile. Gas mileage is measured in mpg. For instance, if your vehicle gets 30 mpg, it travels 30 miles per one gallon of gas.

The mpg is usually higher on highways compared to city driving since city driving necessitates slower speeds, idling, and higher revolutions per minute (rpm). Most vehicles achieve at least five more mpg on the highway than in the city.

Ways to Determine a Vehicle’s Gas Mileage

You can also measure gas mileage in terms of GPM, which is the number of gallons needed to move a vehicle 100 miles. The GPM helps determine the vehicle’s fuel economy when taking other considerations into account.

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  • Type of Vehicle: Smaller engines produce better mileage compared to larger ones because of the vehicle’s weight. The smaller the engine, the lighter the weight and the less fuel needed.
  • Type of Fuel Used: The quality fuel can lower the friction in your vehicle’s engine and can affect the gas mileage.
  • Fuel Octane: The fuel octane’s rating can affect the gas mileage. This number tells the rate at which the engine burns the gas based on the fuel reduction to additive ratio. Higher octane means less burning, which means you’re efficiently operating your vehicle.
  • Type of Driving Conditions: Generally, you get better gas mileage on highways rather than on city streets. The gas mileage is usually about three to five miles more on the highway.
  • How You Drive: Aggressive drivers who speed typically experience worse fuel economy than those who drive slower. When you accelerate quickly from a full stop, it burns more gas than getting up to speed slowly.

Hybrid Fuel Efficiency

A hybrid is another fuel-efficient vehicle to consider. This option uses a gas and electric engine to operate. Its electric motor usually operates the vehicle at slower speeds or when idling before it kicks over to the gasoline engine.

Hybrids can operate more efficiently and cleaner compared to gasoline-powered engines. Although they began as smaller cars, hybrids are available in larger vehicles and SUVs.

Vehicle Condition

Per Green Car Reports, the vehicle’s history also affects fuel economy. A newer or well-maintained vehicle typically attains better gas mileage compared to one with numerous miles or in poor drivable condition. Change the oil and its filter regularly and keep the tires properly inflated to get better gas mileage.

Type of Vehicle

Although it’s tempting to look at a vehicle that gets 50 mpg on the highway and say it’s fuel-efficient, you might not drive that same vehicle. Examine the fuel economy rating for each specific type of vehicle to compare.

For instance, with the 2019 Porsche Boxster, you get 25 mpg combined, while the 2019 Honda Accord LX achieves 31 mpg combined. You might think the Accord gets the better fuel economy; however, the 25-mpg combined with a sports car is a solid number.

Why should you calculate gas mileage?

Calculating gas mileage is important. Not only so you can get an accurate picture of fuel economy, but also spot potential problems with your car/truck. If fuel economy is a lot less than it’s supposed to be- contact your preferred service department.

The Mpg Display in Your Vehicle Might Be Wrong

To make your gas mileage better, you need to know what you are getting in the first place. Most modern vehicles nowadays will have a digital readout. Probably a display on your dash of the mpg (miles per gallon) you are getting.

Gas mileage is determined by the number of miles a vehicle can go on one gallon of gas. Hence the term “miles per gallon (mpg).”

How Many Miles You Can Drive Using One Gallon of Fuel.

This number will vary from about 6mpg to 60mpg depending on the vehicle you drive. The number that is displayed on your dash may not be exactly correct.

Just like a trip computer, these can also be reset. This results in false numbers or erratic driving may also skew the results. Some vehicles may also have an instantaneous mpg readout, which is helpful in bettering driving habits to increase mpg. It’ll tell you’re getting about 70 mpg when you coast. So how do you know what you are really getting?

How to Calculate Gas Mileage?

Take the number of miles that elapsed between tank fills, and divide that by the number of gallons it took to refill your tank. The number you get is how many miles per gallon you are yielding. To simplify, the formula is: miles driven ÷ gallons used = mpg.

Your actual gas efficiency, measured in miles per gallon (mpg) or kilometers per liter (kpl), may vary from the estimates given to you by your manufacturer. That’s because the condition of your vehicle and your style of driving, among other factors, will influence just how much mileage you’ll get after you fill-up.

Calculating Your Car’s Miles per Gallon (MPG)

Fill Up and Record

  • Fill up your gas tank all the way.
  • If your car has a trip odometer, reset it, or record the master odometer mileage.
  • Drive your car as you normally would, and let your gas tank deplete to at least a half of a tank of gas.
  • Get to the gas station and fill your tank again.
  • Record the amount of gas it took to refill the tank.
  • Record the elapsed trip miles or new odometer mileage.


  • Get the miles traveled from the trip odometer, or subtract the original odometer reading from the new one.
  • Divide the miles traveled by the amount of gallons it took to refill the tank. The result will be your car’s average miles per gallon yield for that driving period.

Here’s the formula: miles driven gallons used = mpg

You can perform the same steps to calculate kilometers per liter.

kilometers driven liters used = kpl

Here’s an example: 312 miles driven ÷ 16 gallons fueled = 19.5mpg

Repeating this procedure every time you refill your tank can help you monitor and improve your gas mileage. Improving your fuel efficiency is possible!

But what about the cost? How much does it cost you to drive your car? Finding that out adds another step.

How to Calculate Your Rate of Gas?

You’ve already calculated how many miles (or kilometers) per gallon (or liter) you can drive in your car. Using that number, you can find out how much it costs you to drive your car per distance measured. Here’s how.

Take the average price that you pay at the pumps per gallon and divide that by the number you found when you calculated mpg for your car. Here’s the formula: price per gallon miles per gallon = price per mile

Again, you can use a variation of the same equation to calculate price per kilometer: price per liter kilometers per liter = price per kilometer

Once you’ve found out how much it costs you to travel per unit of measure, you can apply that price to the distance of whatever trip you’re planning. This will tell you how much a given trip will cost in your particular car.

Knowing these amounts can help you improve both your fuel efficiency and your savings every time you drive.