What Does MPG Mean? What Is a Good MPG?

When you’re shopping for a car or even just looking at car ads, you might see the letters “MPG” pop up often. MPG stands for miles per gallon, and it’s important for fuel efficiency.

But what does MPG mean? How do you know if a car’s MPG is “good”?

Let’s break it all down so you can understand what MPG is, how it works, and why it matters when you’re on the road or at the gas pump.

What Is MPG?

MPG stands for miles per gallon—the number of miles your car can travel using one gallon of gas. In other words, it’s a measure of how efficiently your car uses fuel. The higher the MPG, the less often you’ll need to fill up and the more money you save on gas.

Imagine you’re driving a car that gets 30 MPG. This means, with a full gallon of gas, your car can travel 30 miles before you need to refuel.

If you drive a car with 15 MPG, you’ll need to stop for gas more since your car only goes 15 miles on one gallon.

How Is MPG Calculated?

Calculating your car’s MPG is simple, and you can do it yourself with just a bit of tracking. Here’s how:

1. Fill up your car’s gas tank completely.
2. Reset your trip odometer (this shows how many miles you’ve driven since you last filled up).
3. Drive as you normally would until you need gas again.
4. When you fill up the tank again, write how many gallons of gas you added to the tank (this info is usually on the gas pump).
5. Look at your trip odometer to see how many miles you drove since the last fill-up.
6. Now, divide the number of miles driven by the number of gallons you just filled up with.

For example, if you drove 300 miles and used 10 gallons of gas, your MPG would be:

300 miles ÷ 10 gallons = 30 MPG

This is your car’s fuel efficiency for that period of driving. You can repeat this anytime to keep track of your car’s fuel usage.

City vs. Highway MPG: What’s the Difference?

You’ve probably noticed that cars often have two MPG ratings: one for city driving and one for highway driving. But why are they different? It all comes down to the type of driving you do.

• City MPG: When you’re driving in the city, you’re stopping and starting a lot because of traffic lights, stop signs, and slow-moving cars. Each time you stop and then start again, your car uses more fuel. That’s why city MPG is usually lower—it’s less efficient to keep stopping and starting.
• Highway MPG: On the highway, you’re driving at a steady speed with fewer stops, so your car uses fuel more efficiently. This means your highway MPG will be higher than your city MPG.

If a car is rated at 25 MPG city and 35 MPG highway, that means in city conditions, you can drive about 25 miles per gallon of gas, but on the highway, you can drive around 35 miles for each gallon.

Factors That Affect Your Car’s MPG

Not all cars are the same fuel efficiency. Several factors can impact your MPG:

• Driving habits: The way you drive matters. Speeding, sudden stops, and aggressive driving can make your car burn more gas. On the flip side, driving smoothly and maintaining a steady speed helps improve your MPG.
• Car condition: A well-maintained car runs more efficiently. Things like underinflated tires, dirty air filters, or a poorly tuned engine can reduce your MPG. Keeping your car in good shape will keep your MPG as high as possible.
• Weight and cargo: The more weight your car has to carry, the harder the engine works, and the more fuel it uses. Try not to haul unnecessary stuff around in your car—it’s like asking your engine to work overtime.
• Weather: Cold weather can hurt your MPG because your engine takes longer to warm up, and cars use more fuel when they’re cold. Hot weather can also make your car work harder, especially if you’re using the air conditioner all the time.

Does Fuel Type Matter? Gasoline vs. Diesel vs. Electric MPG

Yes, the type of fuel your vehicle uses directly affects its MPG. Here’s a comparison of the most common fuel types:

• Gasoline: This is the standard fuel for most vehicles. Gasoline engines are widely available, but they tend to have lower MPG ratings compared to diesel and electric engines.
• Diesel: Diesel engines are generally more fuel-efficient than gasoline engines because diesel fuel contains more energy per gallon. Diesel-powered cars often achieve higher MPG ratings, especially for long-distance driving.
• Electric: Electric cars don’t use gasoline, so MPGe (miles per gallon equivalent) is their rating. These cars are often more efficient than their gasoline or diesel counterparts, with some models achieving over 100 MPGe.

What Is Good MPG? Average, High, and Low MPG Ratings

What qualifies as “good” MPG varies based on the type of vehicle and its purpose. Here’s a general guide to understanding what’s considered average, high, or low MPG:

• Compact cars and sedans: These vehicles are typically more fuel-efficient because of their lighter weight and smaller engines. 30-40 MPG is good for this category, with some hybrids exceeding 50 MPG.
• SUVs and trucks: Larger vehicles usually have lower fuel efficiency because of their size and power. An average SUV might offer 20-25 MPG, while trucks often fall within the 15-20 MPG range. However, newer models with hybrid technology or advanced engine designs can achieve higher MPG.
• Hybrids and electric cars: Hybrids generally achieve 40-50 MPG, while electric vehicles (EVs) can exceed 100 MPGe, so EVs are the most fuel-efficient option.

Why Is MPG Important for Car Buyers?

MPG plays a crucial role in the total cost of owning and operating a vehicle. Here’s why it matters:

• Cost savings: Higher MPG means fewer trips to the gas station, which translates into lower fuel expenses over time. If you drive long distances regularly, choosing a car with better fuel economy can save you thousands of dollars in the long run.
• Environmental impact: Cars that get more miles per gallon produce fewer emissions, reducing their environmental footprint. If sustainability is important to you, selecting a vehicle with a higher MPG rating can help lower your impact on the planet.
• Resale value: Fuel-efficient cars have a higher resale value because they are cheaper to operate, thus making them more attractive to potential buyers.

How to Find a Vehicle’s MPG Rating?

When buying a car, you can easily find its MPG rating on the Monroney sticker, a label required by law to be displayed on all new cars in the U.S. This sticker lists both the city and highway MPG ratings for the vehicle, allowing you to compare fuel efficiency immediately.

Additionally, websites like fueleconomy.gov provide MPG ratings for almost every vehicle on the market. This site is a reliable resource to check before purchasing a car, whether it’s new or used.

How to Improve Your Car’s MPG

There are some real-world things you can do to optimize your vehicle for the best MPG possible without waiting for an out-of-the-box high MPG rating:

• Drive at moderate speeds: Speeding reduces fuel efficiency. Drive at a moderate, smooth speed to boost your engine’s performance.
• Avoid unnecessary idling: Idling burns fuel without moving the vehicle, wasting gas. Turn off your engine if you stop for more than a minute or two.
• Regular maintenance: Keep your vehicle in top condition by regularly changing the oil, checking tire pressure, and replacing filters. A well-maintained engine runs more efficiently and uses less fuel.

How to Convert MPG to L/100km

In other countries, fuel efficiency is often measured in liters per 100 kilometers (L/100km) instead of MPG. To convert MPG to L/100km, use this formula:

235 ÷ MPG = L/100km

For example, if your vehicle is rated at 30 MPG, the conversion will look like this:

235 ÷ 30 = 7.83 L/100km

This type of conversion is useful if you are a traveler or if you want to buy a vehicle from a country that uses the metric system.

MPG Myths: Debunking Common Misconceptions

You probably hear a bevy of myths regarding MPG that help in furthering confusion. Let’s take a moment to clarify a few of the most common of these:

“Premium fuel improves MPG.” Unless your car specifically requires premium fuel, there is absolutely no way you’ll improve your MPG by putting it in.

“Manuals get better MPG than automatics.” This was true in the past, but modern automatic transmissions are highly efficient. They often match or even surpass the fuel efficiency of manual cars.

“The AC is always burning fuel when it’s on.” While it’s true that running the air conditioner uses energy, rolling down your windows at high speeds can increase drag and reduce fuel efficiency, potentially negating any savings.

Conclusion

Knowing about MPG is important. This is true if you are buying a new car. It also helps you save fuel, or you might just be curious about how people use fuel.

Higher MPG saves you money and helps the environment. It also supports a more sustainable future.

By choosing a vehicle that uses fuel well and driving smart, you can get the most from every gallon. This helps you make the best use of your time on the road.