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Summary
  • Your vehicle’s gas mileage is essentially how many miles it can travel per gallon of gas. It’s measured in miles per gallon, or MPG for short.
  • To calculate your vehicle’s gas mileage, follow the steps in this article, including filling up your vehicle’s gas tank, resetting the odometer, and doing the math.
  • Your vehicle’s type, its fuel, and the environment you drive in all affect gas mileage. Vehicles with the best gas mileage tend to reach 22 MPG or higher.
  • Knowing your vehicle’s gas mileage gives you a good idea of its performance on your daily drives. You’ll also be more aware of your vehicle’s environmental impact and how much money it costs for you to drive anywhere.

Have you ever wondered how far you can drive on a full tank of gas? It depends on the vehicle. Many manufacturers will advertise their vehicles’ gas mileage, but it would be nice to see if reality matches their claims. We’ll go over how to calculate your vehicle’s gas mileage, why you should care, and more.

How To Calculate Gas Mileage

Your vehicle’s gas mileage is essentially how many miles it can travel per gallon of gas. Thankfully, calculating gas mileage is a fairly simple process. Here are the steps for calculating gas mileage, along with some advice to make the process easier:

Fill Up Your Vehicle’s Tank

The first step is to completely fill up your vehicle’s gas tank. Just let the pump automatically shut off once your tank is full. There’s no need to take down any numbers in this step.

Reset the Trip Odometer

Next, you’ll want to reset your vehicle’s trip odometer. Many vehicles come with a trip odometer for measuring the exact distance the vehicle traveled during a specific trip. Keep in mind that the trip odometer is separate from your vehicle’s lifetime odometer. If your vehicle doesn’t have a trip odometer, then take note of its lifetime odometer’s current mile count.

Drive Around for a Few Miles

After filling up your vehicle’s fuel tank and resetting its trip odometer, you’ll need to take a drive. Drive around for a few miles on your usual routes and at your usual speeds. Different things can affect your vehicle’s gas mileage. If you hurry the test and drive faster than usual, your results might not be an accurate representation of your vehicle’s typical gas mileage on a normal day.

Refill Your Tank and Note the Gallons Consumed

Once you’re done with your test drive, pull up to a gas station and fully fill up your tank again. Take note of how much fuel went into your tank. This is an important number that you’ll use for your calculations later. You can also find the exact number of gallons you bought on your gas station receipt.

Note the Trip Meter Reading

Before leaving the gas station, also note down your trip odometer’s reading. It’ll show you the exact number of miles you drove. If your vehicle doesn’t have a trip odometer, simply take down the lifetime odometer’s new reading and subtract the first reading from the new reading to find out how many miles you drove.

Divide the Miles on Your Trip Meter by the Number of Gallons You Topped Up

Next, you need to divide the number of miles you drove by the number of gallons you topped up at the gas station. The resulting number is your vehicle’s gas mileage, or the number of miles it can travel on a single gallon of gas. This unit is called miles per gallon, or MPG for short. Here’s the full equation for calculating your gas mileage:

Miles driven / gallons used = gas mileage (miles per gallon)

What Affects Gas Mileage?

Many different factors affect your vehicle’s gas mileage. Before we delve into whether your vehicle’s gas mileage is good or not, you need to understand that the answer differs depending on the vehicle’s class, its fuel type, and the driving environment, among other things.

Vehicle Type

Your vehicle’s type affects gas mileage. Smaller engines use up less gas and are typically found on lighter cars. A small sedan will likely have better gas mileage numbers than a six-seater crossover, but the crossover might have better gas mileage compared to other crossovers. It’s all a matter of perspective in this case.

Fuel and Environment

Fuel quality and fuel octane ratings affect your vehicle’s engine, which in turn affects how much fuel it burns. In addition to this, driving conditions also factor into the equation. It takes less fuel to drive down a highway than it does to climb a hill.

Driving Habits

How aggressively you drive also affects fuel economy. Accelerating right away from a full stop burns up more fuel than a slow buildup. If you’re an aggressive driver who accelerates a lot, you might find you’re using up more fuel than a passive, slow driver driving the exact same vehicle.

What Is Considered Good Gas Mileage?

Now that you know your vehicle’s gas mileage, you might be wondering if it’s good or not. The U.S. Environmental Protection Agency (EPA) keeps track of the most fuel-efficient vehicles, and you can check their list for more concrete answers. In 2020, vehicles that reached 22 MPG combined or higher topped the EPA list.

Again though, good gas mileage depends on your needs. As we mentioned, bigger vehicles tend to have worse gas mileage than smaller ones. If you need a big vehicle, then one that uses the least gas per mile would have good gas mileage for your needs.

Other Gas Mileage Calculations

If you’re wondering how to calculate gas mileage cost, simply divide the current cost of fuel per gallon by your vehicle’s MPG. That’ll show you how much you’re spending per mile of travel. That’s also the first step for how to calculate gas mileage costs for a trip. From there, simply multiply the cost per mile by the number of miles you’ll be driving on the trip, and you’ll have a rough estimate of how much your gas will cost for that trip.

Why Calculate Gas Mileage?

So what’s the point of calculating your vehicle’s gas mileage? For starters, you get a good idea of your vehicle’s performance on your daily drives. Poor fuel economy is typically a sign that something’s wrong with your vehicle. Knowing your usual gas mileage might help you realize there’s a problem sooner.

It also helps you stay aware of your vehicle’s environmental impact and how much money it costs for you to drive anywhere. This can help you budget your resources, and it can also help you decide if it’s time to buy a new vehicle that uses up less fuel. In the end, your vehicle’s gas mileage is a handy thing to know, and now you can calculate it yourself with ease.

About The Authors
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Automotive Features Reviewer at CarParts.com

Lisa Conant grew up in Canada around a solid contingency of gear heads and DIY motor enthusiasts. She is an eclectic writer with a varied repertoire in the automotive industry, including research pieces with a focus on daily drivers and recreational vehicles. Lisa has written for Car Bibles and The Drive.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

File Under : Driving , For the Car Owner
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