Fuel Economy Converter
Fuel Economy Converter US MPG imperial MPG conversion L per 100 km converter km per liter to mpgTranslate between common economy formats
Enter a positive fuel-economy value and choose source and destination formats. The converter handles US and imperial gallons separately and correctly reverses consumption-style liters per 100 kilometers.
Distance-per-fuel and fuel-per-distance
MPG and kilometers per liter rise when efficiency improves. Liters per 100 kilometers moves in the opposite direction: a lower value uses less fuel for the same trip. Converting between these families requires taking a reciprocal, not only multiplying by a fixed unit factor.
US and imperial gallons differ
One US liquid gallon is 3.785411784 liters. One imperial gallon is 4.54609 liters. An identical vehicle therefore has a larger numerical imperial MPG than US MPG. A label that says only “MPG” is ambiguous without its regional gallon definition.
Worked example
Thirty US MPG converts to about 7.8405 L/100 km, 36.0283 imperial MPG, or 12.7543 km/L. Reversing 7.8405 L/100 km returns approximately 30 US MPG, with a small display difference possible from rounding.
Conversion constants
The page uses exact meter, mile, US gallon, and imperial gallon relationships to normalize through US MPG. For positive values, US MPG equals 235.214583 divided by L/100 km. Kilometers per liter multiplied by about 2.352146 gives US MPG.
Rated and real-world economy
A unit conversion does not predict actual use. Speed, temperature, terrain, traffic, payload, tire pressure, fuel blend, driving style, trip length, accessories, and measurement method change observed economy. Compare ratings made under compatible test procedures.
Limitations and privacy
The tool accepts only positive finite values because zero cannot be reciprocally converted. It does not estimate fuel cost, emissions, range, electric efficiency, or vehicle condition. No value is sent anywhere.
Fuel Economy FAQ
Is higher always better?
Higher is better for MPG and km/L; lower is better for L/100 km.
Why is imperial MPG larger?
The imperial gallon contains more liters than the US gallon.
Can it calculate trip fuel cost?
No. Use Fuel Cost Calculator with trip distance and fuel price.