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For generations, Americans have been measuring fuel efficiency by miles per gallon. But not only is that metric wildly variable depending on who is doing the testing, it is also hard to calculate what it means for you, the end user. However, there is another way to find a car with the best fuel mileage, and it’s been hidden in plain sight all along.

New numbers on the window sticker make it easy to find the best fuel mileage

An older window sticker with antiquated fuel economy measurements
This older window sticker doesn’t include the new measurement | Getty Images

On the window sticker of any new vehicle you’ll buy, the EPA-estimated miles per gallon figure is prominently displayed. It’s big, it’s bold, and it’s likely the first number to catch the eye. However, in smaller type just below that figure is the gallons-per-100-miles rating. Instituted in 2012, Popular Science says that this number is a much better way to find the best fuel mileage when comparing vehicles.

An easier way to compare fuel economy

High fuel costs will continue, so understanding fuel economy is important
Understanding fuel efficiency can help save at the pump | Getty Images

While the basic premise of both measurements is the same, using the gallons-per-100-miles figure makes comparing vehicles easier. That’s because in this method, gains in efficiency are linear, while MPG measurements are graded on a curve.

It’s much easier to understand how using 5 fewer gallons per 100 miles will save money and burn less fuel. Meanwhile, a 5 mpg improvement will mark a 33% gain for a 15mpg vehicle, but just a 17.5% improvement for a 30 mpg vehicle. That can make calculating actual efficiency gains much more difficult.

Clarity when car shopping

Buying a new car is already a complex endeavor, whether you go to a dealership or buy online. However, using the EPA’s updated metric will, at least, make calculating overall fuel costs considerably easier. Of course, the EPA stickers also include annual fuel cost, though that will vary greatly based on how much you actually drive.

Instead, using the gallons-per-100-miles measurement lets you accurately calculate how much you’ll spend based on your current driving habits. That makes it a much more useful figure, and it involves less math than traditional MPG measurements as well.

Located just beneath the big MPG numbers, this alternative fuel efficiency figure isn’t hard to find. It’s just not the first one that most of us notice when we search for the right car. And while of course, it doesn’t change the literal efficiency of the vehicle, it can help reveal small changes in efficiency on similar vehicles.

Europe has been using similar measurements for years

This window sticker includes the better way to find the best fuel economy
An updated window sticker with more efficiency data | Getty Images

Much like their use of the Metric system, European car buyers have used this simpler form of measurement for decades. Theirs, naturally, is liters per 100 kilometers, but the basic formula is the same. Meanwhile, the Imperial version of this figure has featured on EPA stickers since 2012, but few have noticed the change. Old habits are hard to break, after all, but that doesn’t mean there isn’t a better way of doing things.

Of course, as electric vehicles become more prominent, knowing how to parse fuel economy numbers may not matter for much longer anyway. But for the immediate future, consider looking at the smaller fuel economy numbers and enjoy an easier way to find the best fuel mileage for your next car. 

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