Fuel Efficiency Converter

The Fuel Efficiency Converter helps you translate between the most common fuel economy units used around the world. Whether you are comparing vehicle specifications listed in miles per gallon with European ratings in liters per 100 kilometers, or converting between US and UK gallon-based measurements, this tool gives you accurate results instantly.

Fuel efficiency measurement varies significantly by region. The United States uses miles per US gallon (MPG US), where the US gallon equals 3.78541 liters. The United Kingdom historically uses miles per imperial gallon (MPG UK), where the imperial gallon equals 4.54609 liters. Most of continental Europe and many other countries express fuel economy in liters per 100 kilometers (L/100km), which is an inverse measure where lower numbers indicate better efficiency. Some Asian countries prefer kilometers per liter (km/L), which is a direct measure like MPG.

The tool handles the tricky relationship between direct and inverse units correctly. Units like MPG and km/L are direct measures where higher values mean better efficiency, while L/100km is an inverse measure where lower values are better. The converter uses km/L as the internal base unit and correctly inverts L/100km values during conversion, so you always get accurate results regardless of which direction you are converting.

All calculations run entirely in your browser. No data is transmitted to any server, keeping your inputs private. Results are shown with up to six decimal places, with trailing zeros trimmed for readability.