MPG & L/100 km converter
Convert MPG to L/100 km, or L/100 km to MPG. Choose US or Imperial gallons, enter your fuel figure, and compare all three results.
MPG conversion reference
Each row describes the same fuel consumption in three units. These are conversion examples, not expected results for a particular truck.
Use fuel consumption in a trip-cost example| US MPG | Imperial MPG | L/100 km |
|---|---|---|
| 6.00 | 7.21 | 39.20 |
| 8.00 | 9.61 | 29.40 |
| 10.00 | 12.01 | 23.52 |
| 20.00 | 24.02 | 11.76 |
| 30.00 | 36.03 | 7.84 |
| 40.00 | 48.04 | 5.88 |
How the math works
One mile is exactly 1.609344 km. One US gallon is exactly 3.785411784 L; one Imperial gallon is exactly 4.54609 L.
Imperial MPG = 282.480936331… / (L/100 km)
Reverse either equation to obtain L/100 km. The calculation uses the full definition-based factors; displayed results are rounded.
A useful cross-check
30 L/100 km is approximately 7.84 US MPG or 9.42 Imperial MPG. These describe the same consumption, not different vehicle performance.
Zero is not convertible: the reciprocal would divide by zero. Use a positive value with its original unit.
Estimate trip fuel cost →Sources & limits
Conversions use defined units. Road conditions, load, idling and measurement accuracy remain part of your original fuel figure.
Common questions
Does 6 mpg mean the same thing with US and Imperial gallons?
No. 6 US mpg converts to about 39.2 L/100 km, while 6 Imperial mpg converts to about 47.1 L/100 km. Choose the gallon type used by the original figure before comparing results. Changing the unit label alone does not convert the number.
What is 30 L/100 km in mpg?
30 L/100 km is approximately 7.84 US mpg or 9.42 Imperial mpg. All three describe the same consumption. Lower L/100 km means less fuel per distance; higher mpg means more distance per gallon. Compare like units, and remember that displayed conversions are rounded.
Do the header’s currency and distance choices change this converter?
No. This tool uses the input unit selected inside the converter and always labels its three results as L/100 km, US mpg and Imperial mpg. Currency and distance preferences in the header do not change those results. Use a positive value; zero cannot be converted by the reciprocal formula.