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MPG Converter

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Fuel economy conversionFAQs

This miles per gallon (MPG) converter enables you to quickly and easily swap between units used in fuel economy conversions. The units available in this MPG converter are:

  • Miles per US gallon;
  • Miles per UK gallon;
  • Liters per 100 kilometers; and
  • Kilometers per liter.

Keep in mind that these units are inversely proportional (that is, as one decreases, the other increases, and vice versa). An efficient car consumes a low amount of gasoline per 100 kilometers but can travel many miles on a gallon.

This MPG converter can serve as a useful tool when ordering a car from abroad. Make sure you also have it with you when you are traveling in a country with different fuel economy units, as the differences between them are quite significant.

Our gas calculator is closely related to these issues, as it lets you calculate the total cost of a car trip based on mileage, distance, and gas price.

Fuel economy conversion

Fuel economy is the relationship between the distance a vehicle travels and the amount of fuel it consumes. When calculating, it's important to distinguish between the US and imperial gallon as they represent different values. US gallons are used mostly in the United States (unsurprisingly) but also in some Caribbean and Latin American countries. Imperial gallon is a unit you can encounter in some Commonwealth countries such as the United Kingdom and Canada. Liters per 100 kilometers are used almost anywhere else on the planet.

Another important difference is between the measurement systems — when using miles (either imperial or US) per gallon, the higher the value, the more efficient the vehicle is. On the other hand, those using liters per 100 km usually hope for a lower score as it results in smaller gas bills. 1 liter per 100 kilometers equals 235.2 US MPG or 282.5 Imperial MPG. At the same time, 1 US MPG equals 235.2 liters per 100 km. 1 US MPG = 1.201 UK MPG, while 1 UK MPG is 0.8327 US MPG. These are the basic equations of fuel economy conversion.

If you want to go deeper into the topic, check out our speed calculator, which deals with the trinity of time, distance, and speed; while the acceleration calculator deals with how the velocity changes over time or how much a given force moves an object with a given mass by.


How to improve fuel economy?

Here are some tips you could use for improving fuel economy:

  1. Drive at speeds around 60-65 mph (95-100 km/h). Cars consume fuel more efficiently at that speed.

  2. Keep your tires full of air.

  3. At speeds above 50 mph (80 km/h), it is highly recommended to close the windows and use the AC instead, as the wind increases resistance and makes the car consume more fuel.

What is a good fuel economy?

There are different ways to measure fuel economy.

  • "The lower, the better" if we are using liters per 100 km (ℓ/100 km).

  • "The higher, the better" if we use the English metric system (miles per gallon or mpg).

Famous car blogs indicate that anything less than 6 liters per 100 km is excellent. Omnicalculator's fuel economy conversion tool shows that 6 ℓ/100 km equals 39.2 US mpg.

How to find out the fuel economy of my car?

Here is a practical method to calculate fuel economy:

  1. Fill your tank to the brim.
  2. Set the odometer to zero.
  3. Drive normally, the longer you drive, the better.
  4. Fill the tank to the brim again, however fuel you put in, that's the fuel you consumed on your trip.
  5. Divide the miles you drove (as marked by the odometer) by the fuel you consumed in gallons. That's your fuel economy in mpg!

How to convert fuel economy from US mpg to liters per km?

  1. Make a not of your fuel economy in mpg
  2. Divide 2.352 by your fuel economy in mpg
  3. The result is your fuel economy expressed in liters per kilometer
  4. If you want the fuel economy in liters per 100 kilometers, just multiply the result of step 2 by 100.
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