US road trip and national park tools

MPG to L/100km Converter

Enter a fuel economy figure in mpg, L/100 km or km/L and see it in every unit at once, with the arithmetic shown.

This free MPG to L/100km converter changes a fuel economy figure between miles per gallon and liters per 100 kilometers, and between other common units too. Type a number, pick its unit, and the page shows the same figure in every other unit at once. The tool runs in your browser, so nothing you type is sent anywhere. It converts fuel economy only. It does not rate a vehicle or show fuel cost. Use it when a brochure, review or fuel label quotes one unit and you need another. A US shopper reading a Canadian or European spec sheet sees L/100 km, a UK driver may see mpg based on the larger imperial gallon, and a trip planner may want km/L. The converter handles all of these, and it shows the arithmetic so you can check the answer or repeat it by hand.
Mpg to l/100km example

How to use the MPG to L/100 km converter

  1. Click the Fuel economy to convert field and type a number, such as 30.
  2. Open the unit menu beside the field and choose mpg (US), mpg (UK), L/100 km or km/L.
  3. Read the main result, Liters per 100 km. It updates as you type, so there is no Convert button to press.
  4. Check the other results: Miles per US gallon, Miles per imperial (UK) gallon, Kilometers per liter and US gallons per 100 miles.
  5. Scroll down to the list that shows the arithmetic, or to the two reference tables for common values.
  6. If you see a warning, the figure converts to more than 150 or less than 3 mpg (US). Zero, negative or non-numeric input shows an error that names the field.

Four preset chips (30 mpg, 8 L/100 km, 45 mpg (UK) and 15 km/L) fill the field in one click, which is a quick way to see how each unit reads. The two reference tables list common values, so you can look up 25 mpg or 10 L/100 km without typing anything. To convert a different figure, change the number or switch the unit menu and every result updates at once. Pick the unit your source quoted, not the one you want back, because the tool converts from the unit in the menu. Copy link, print and share buttons are available for the results.

How do I convert mpg to L/100 km?

Divide 235.2146 by the mpg (US) figure. For example, 235.2146 ÷ 30 = 7.84 L/100 km. The constant comes from 100 × 3.785411784 liters per US gallon, divided by 1.609344 km per mile. Both values are exact conversion factors from NIST SP 811. Other examples: 20 mpg is 11.76 L/100 km, and 40 mpg is 5.88.

How do I convert L/100 km to mpg?

Divide the same constant, 235.2146, by the L/100 km figure. For example, 235.2146 ÷ 8 = 29.40 mpg (US). The formula is reversed in the same way, so 7.84 L/100 km converts back to 30 mpg.

Is UK mpg the same as US mpg?

No. An imperial (UK) gallon is 4.54609 liters, while a US gallon is 3.785411784 liters, so the same number means different things. One mpg (UK) equals 1.20095 mpg (US). For UK figures, use L/100 km = 282.4809 ÷ mpg (UK). For example, 45 mpg (UK) is 6.28 L/100 km, which is 37.47 mpg (US).

Why is a lower L/100 km number better?

The two scales run in opposite directions. L/100 km measures how much fuel a vehicle uses to cover 100 km, so less fuel is better. Mpg measures how far a vehicle travels on one gallon, so more miles is better. A car at 8 L/100 km is the same car as one at 29.40 mpg (US), and 5.88 L/100 km is 40 mpg.

How do I convert mpg to km/L?

Multiply the mpg (US) figure by 0.425144, which is 1.609344 ÷ 3.785411784. For example, 30 mpg × 0.425144 = 12.75 km/L. You can also divide 100 by the L/100 km figure. Going the other way, 8 L/100 km is 12.5 km/L, and 15 km/L is 6.67 L/100 km, or 35.28 mpg (US).

How much fuel does a trip use at a given L/100 km?

This tool converts units only, but the conversion helps you read other numbers. Fuel used = distance × economy. A 500-mile trip at 30 mpg uses 500 ÷ 30 = 16.67 US gallons, which is 63.1 liters. The same trip is 804.7 km, and at 7.84 L/100 km that is 804.7 ÷ 100 × 7.84 = 63.1 liters. Both routes give the same fuel because 30 mpg and 7.84 L/100 km are the same economy. To turn fuel into money, use the gas cost calculator.

Worked examples

InputResult
30 mpg (US)7.84 L/100 km = 30.00 mpg = 36.03 mpg
25 mpg (US)9.41 L/100 km = 25.00 mpg = 30.02 mpg
8 L/100 km8.00 L/100 km = 29.40 mpg = 35.31 mpg
45 mpg (UK)6.28 L/100 km = 37.47 mpg = 45.00 mpg
15 km/L6.67 L/100 km = 35.28 mpg = 42.37 mpg

Calculated by the tool above; open it with the same values to see each step.

Frequently asked questions

Does this tool give fuel cost?

No. It converts fuel economy only and shows no fuel cost. To work out cost, use the gas cost calculator, or the gas mileage calculator, which can also find mpg from a fill-up.

Which units do cars use in the US and Canada?

US vehicles are rated in mpg, according to fueleconomy.gov. Canada rates vehicles in L/100 km. The EPA fuel economy label also prints gallons per 100 miles.

What is US gallons per 100 miles?

It is 100 ÷ mpg (US), so 30 mpg equals 3.33 US gallons per 100 miles. A lower figure means better efficiency, as with L/100 km.

Can I convert electric vehicle MPGe here?

No. MPGe for electric vehicles is not a fuel-economy figure for this tool, so enter only figures for vehicles that burn fuel.

Why did the tool show a warning?

The warning appears when the figure converts to more than 150 or less than 3 mpg (US). Check the number and the unit you selected.

Does the tool tell me whether a value is good?

No. It does not rate vehicles or say what a good value is. It only converts the number you enter.

Is anything I type sent to a server?

No. The tool runs in your browser, and nothing you type is sent anywhere.