What Is MPG? [+ How To Improve It]

Fuel efficiency is the top consideration for most new car buyers in 2023. While some buyers may be looking for fuel efficiency to protect their wallets, others want to protect the environment. Either way, they'll use a vehicle's miles per gallon rating as a key factor in their decision. But what is mpg?

Learn more about this figure and discover how and why you should be factoring it yourself. We'll also help you compare your mpg to other cars and offer tips for improving your miles per gallon to keep your wallet and the environment happy.

What Is MPG?

MPG, an abbreviation for miles per gallon, refers to the distance in miles that your vehicle can cover using one gallon of fuel.

For example, if your car's mpg is 35 mpg, you can travel 35 miles in one gallon of gas. Every vehicle, whether it is gasoline- or diesel-powered or a hybrid, will have an official mpg rating with a few exceptions:

• Motorcycles
• Passenger vehicles with a Gross Vehicle Weight Rating (GVWR) of 10,000+ pounds
• Cargo vans with a GVWR of 8,500+ pounds
• Pickup trucks with a GVWR of 8,500+ pounds and an interior bed length of 72+ inches

Understanding your car's miles per gallon rating is important to help you determine how far you can travel on one tank of gas. If you can travel 35 miles on one gallon, and your tank holds 10 gallons, you can expect to travel about 350 miles on one tank. However, miles per gallon figures are estimates, so don't count on going exactly 350 miles before filling up or you risk running out of gas and needing to call roadside assistance for a tow.

The Environmental Protection Agency (EPA) certifies and reports vehicle's miles per gallon ratings after a series of road and lab tests that address various factors that impact miles per gallon, such as city and highway driving conditions. They report three different ratings:

• Highway mpg: Cars typically get a higher average mpg on the highway because they travel at a higher speed consistently for a longer distance.
• City mpg: City driving involves frequent starting and stopping and lower speeds, which decreases fuel economy.
• Combined mpg: This figure is an average of a vehicle's highway and city mpg.

You can find your vehicle's miles per gallon rating on its window tag at the dealership, called a Monroney label, or search for the EPA's fuel economy website.

How To Calculate Your MPG

Miles per gallon figures are estimates and do not reflect €œreal world€ driving situations, so you should calculate your miles per gallon yourself. Fortunately, doing this easy:

1. Fill up your gas tank completely.
2. Reset your trip odometer. How to do this varies by vehicle make and model, so check your owner's manual.
3. Drive normally until your tank is almost empty.
4. Fill up your tank completely.
5. Divide the miles on the trip odometer by the number of gallons you need to fill your tank, which will be on the receipt or the gas dispenser screen.

For example, if you drive 375 miles before filling your tank, and it takes 9.5 gallons to fill your tank, you would divide 375 by 9.5. Your mpg would be about 40.

Newer cars may be able to calculate your mpg for you in real time. It may show up on the dashboard display or infotainment screen.

Knowing your vehicle's miles per gallon rating is helpful for two reasons:

1. It helps you budget expected fuel costs. Use your car's miles per gallon figure to calculate how frequently you'll have to fill up your tank. For example, if you commute 30 miles to and from work each day, and your mpg is 30, you can expect to use a gallon of fuel every day. With a 10-gallon tank, you'll need to fill up every 10 days.
2. It monitors your car's performance. If your driving habits are roughly the same each week and you notice your miles per gallon figure decreasing over time, this may be a sign that something is wrong with your car. Take your car to an auto repair facility to discover the problem before it worsens.

How To Convert MPG to L/100 km

Drivers in America use miles, but drivers in places like Canada and Europe use kilometers, so you'll need to know how to convert mpg to L/100 km. However, American gallons and European gallons are different, American gallons equal 3.79 liters, while European gallons are imperial gallons and equal to 4.55 liters.

If the miles per gallon figure is in imperial gallons, divide 282.5 by the miles per gallon figure. If a car has an mpg of 40, you would divide 282.5 by 40 and get 7.1 L/100 km.

If the miles per gallon figure is in U.S. gallons, you'll divide 235.2 by the miles per gallon figure: 235.21/40 = 5.9 L/100 km.

What Is a Good MPG?

In general, the higher your miles per gallon, the better, and what is considered a good miles per gallon for one vehicle will not be the same for a different make or model. Instead, compare your miles per gallon to the U.S. average mpg, which in 2021 was 25.4 mpg, or the average gas mileage for your vehicle type.

Factors Influencing MPG

Miles per gallon is an average reflecting different factors that influence the fuel efficiency of a vehicle, which means the miles per gallon you experience while driving your car may not exactly match the official mpg rating. Your miles per gallon may be higher or lower depending on various factors:

1. Driving habits: Aggressive driving, which includes quick acceleration and hard stops, lowers gas mileage. Hauling heavy loads or towing trailers or other vehicles also reduces gas mileage.
2. Vehicle condition: Newer cars tend to have better mpg than older vehicles, partly due to newer technology but also because of worn-out parts that aren't functioning correctly. Old oil, dirty filters or fuel injectors, or improperly balanced or pressurized tires can all decrease a car's fuel efficiency.
3. Road conditions: When driving on a flat straight stretch of road with minimal stops, you'll experience a higher miles per gallon rating than if you are driving up and down hills or making frequent stops
4. Environmental conditions: Colder weather can cause your car to run less efficiently, slightly lowering your miles per gallon rating.
5. Vehicle type: Larger and heavier vehicles tend to have a lower miles per gallon rating because they require more power to move than smaller, lighter cars. Other vehicle factors that impact your fuel efficiency include:

• Two-wheel drive versus Four-wheel drive capability
• Hybrid drivetrain
• Sport versus eco or econ mode
• Engine size (measured in liters)
• Aerodynamics of the body

How To Improve Your MPG

Fortunately, improving your miles per gallon is possible by changing your driving habits and properly maintaining your vehicle.

1. Plan the most fuel-efficient route for every trip. Many navigation apps will now offer an eco-friendly route in addition to the quickest.
2. Combine trips when possible. Instead of driving across town to eat at your favorite restaurant, wait until you have another reason to drive that way, such as stopping at the pharmacy in the same shopping center.
3. Follow your vehicle's maintenance schedule. Ensuring everything is in working order keeps your car performing at its best, which can increase your mpg.
4. Only use the fuel recommended in the owner's manual. Using the wrong fuel can decrease your car's performance and fuel efficiency.
5. Use cruise control on the highway. Cruise control allows you to maintain a steady speed for long stretches, which can increase your fuel efficiency. Newer car models can also slowly decelerate in cruise control when you approach a car in front of you to avoid suddenly slamming on the brakes, impacting your fuel efficiency.
6. Keep an eye on your tires. For best performance, check your tire pressure frequently to ensure your tires are properly inflated. Rotate your tires according to the manufacturer's recommendation and keep them aligned and balanced.
7. Avoid accelerating excessively. When driving in the city, accelerate slowly and steadily and avoid sudden braking whenever possible.
8. Remove excess weight from your car. Empty the trunk of everything you don't need and remove any outside storage like a roof box when you don't need it. 100 pounds of weight can decrease fuel economy by one percent.
9. Use Eco or Econ mode. Modern vehicles often have an Eco or Econ mode that reduces the amount of power the engine produces. This means your AC won't run as hard, and you won't be able to accelerate as quickly, but you improve your miles per gallon rating.
10. Avoid idling. Idling burns fuel but does not move the vehicle, lowering your overall fuel efficiency. While some idling is unavoidable, some modern cars have automatic shut-offs that will turn the engine off while you are stopped and automatically restart it when you press the gas pedal.
11. Stick to the speed limit. Every five miles per hour over 60 mph can decrease your vehicle's fuel efficiency by 7 percent.

Keep Your MPG High With AAA

Get the best miles per gallon with regular maintenance to keep your car performing its best. Schedule an appointment at one of AAA's 7,000 approved auto repair facilities, which are only staffed by Automotive Service Excellence (ASE)-certified or factory-trained technicians. All work comes with a 24-month/24,000-mile warranty and fair pricing.

With your AAA membership for priority service and savings on labor costs for any repairs, or if you run out of gas, one of our roadside assistance providers will bring you enough gas to get you to the nearest gas station.