Why is U.K. MPG higher than U.S. MPG?

The U.K. uses a larger imperial gallon (4.546 liters) compared to the U.S. gallon (3.785 liters). That makes U.K. MPG numbers look higher, even if the actual fuel efficiency is the same.

How do I convert MPG to L/100km?

You can use the calculator on this page, or apply the formula: L/100km = 235.215 ÷ MPG (U.S.).

What is a good fuel economy rating?

It depends on the type of vehicle. For gas-powered cars, 30+ MPG is solid. For hybrids, 4–6 L/100km is excellent. Diesel vehicles doing 15+ km/L are considered very efficient.

What’s the difference between MPG (U.S.) and MPG (U.K.)?

MPG (U.K.) is based on a larger gallon. That’s why the same vehicle will report a higher MPG in the U.K. than in the U.S., even if it’s using the same amount of fuel.

Can I use this to compare EVs too?

Yes. While EVs use MPGe (miles per gallon equivalent), this tool helps you better understand gas and hybrid fuel use so you can compare savings more accurately.

Fuel Economy Converter – Convert MPG, L/100km, and More

🔍 About This Fuel Economy Converter

Understanding fuel efficiency can get confusing — especially when comparing vehicles across countries. That’s where our Fuel Economy Converter comes in.

This tool allows you to instantly convert between:

Green fuel nozzle dispensing gasoline with a droplet at the tip, set against a sleek dark background.

Miles per gallon (U.S.)
Miles per gallon (U.K.)
Liters per 100 kilometers (L/100km)
Kilometers per liter (km/L)

⛽ Fuel Economy Converter: U.S. MPG vs. U.K. MPG vs. L/100km

One day, I was chatting with other Kia Sportage HEV owners on Reddit, comparing fuel economy numbers. A friendly gentleman from the U.K. chimed in and claimed his Sportage was getting much better mileage than mine.

That didn’t make sense.

Was it the climate? Altitude? Hemisphere? Proximity to the equator?
Solar storms? Magnetic fields?

Nope—it was the size of the gallon.

It turns out the U.K. uses Imperial gallons, which are about 20% larger than the U.S. gallons we use. So when someone in the U.K. says they’re getting 50 MPG, that’s not apples to apples. It’s more like apples to grapefruits.

🚨 Wait—Why Doesn’t Everyone Know This?

That was the biggest surprise: almost no one talks about this.
It’s not plastered on EPA labels. It’s not mentioned on most auto forums. Yet it has a huge impact on how we compare fuel efficiency across countries.

Once you know this, you’ll never feel inferior again when comparing your MPG to someone overseas.

🔁 Use This Calculator to Convert:

U.S. MPG ⇄ U.K. MPG
MPG ⇄ L/100km
Liters ⇄ Gallons

Simple, quick, and accurate—so you can finally compare fuel economy like a pro.

Fuel economy comparisons shouldn’t be confusing.
They just need the right conversion.

MPG Conversion Calculator

Enter Value

Convert From

Whether you’re comparing global car specs or just want clarity on your vehicle’s fuel efficiency, this tool makes it quick and easy.

🌍 Why Use It?

Fuel economy numbers can be misleading if you don’t know how they’re measured. A U.K. gallon is about 20% larger than a U.S. gallon, which makes U.K. MPG figures look better — but that doesn’t always mean greater efficiency.

For official fuel efficiency ratings, vehicle comparisons, and annual fuel cost estimates, visit the U.S. Department of Energy’s FuelEconomy.gov site.

If you’re curious about how different countries measure fuel economy, this Wikipedia article on fuel economy in automobiles explains various standards including MPG, L/100km, and km/L.

For European car buyers or those comparing imported models, check out how the WLTP (Worldwide Harmonized Light Vehicles Test Procedure) works — it’s Europe’s current fuel efficiency testing standard.

This calculator lets you:

🔁 Translate fuel ratings across countries
🚘 Compare real-world fuel costs
🌿 Understand EV and hybrid efficiency formats
🧮 Get clarity on MPG, L/100km, and km/L instantly

🚗 Who It’s For:

Drivers comparing U.S. vs. international fuel economy specs
Car shoppers and lease hunters
EV and hybrid owners watching efficiency
Anyone who wants to decode fuel economy numbers

✅ Want to Save Money on Fuel-Efficient Cars?

👉 View the Best EV & Hybrid Lease Deals →