Miles per US gallon and liters per 100 kilometers
US miles per gallon is the distance in miles driven on one US gallon (3.785 L). EPA window stickers and car reviews in the US quote mpg.
Liters per 100 km is the fuel needed to drive 100 kilometers; lower numbers mean better economy. Europe, Canada, Australia and China rate fuel consumption in L/100 km.
Worked example
Convert 35 mpg with L/100 km = 235.214583 ÷ mpg: the result is 6.720416667 L/100 km. Likewise 30 mpg = 7.840486111 L/100 km.
Estimating in your head
Divide 235 by the mpg figure: 35 mpg is about 6.7 L/100 km.
Going the other way
To convert liters per 100 kilometers to miles per US gallon, type in the right-hand box; the page solves the same formula backwards. The swap button between the boxes opens the reverse page.
How this works
L/100 km = 235.214583 ÷ mpg
One of these measures distance per fuel and the other fuel per distance, so they are reciprocals and the conversion is a division. The constant 235.214583 comes from 100 km and the exact mile (1.609344 km) and US gallon (3.785411784 L). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
What is the formula to convert miles per US gallon to liters per 100 kilometers?
L/100 km = 235.214583 ÷ mpg. It is exact; for example 35 mpg = 6.720416667 L/100 km.
How do I convert miles per US gallon to liters per 100 kilometers?
Use L/100 km = 235.214583 ÷ mpg. For example, 30 mpg = 7.840486111 L/100 km.
What is 40 mpg in liters per 100 kilometers?
40 mpg = 5.880364583 L/100 km. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST Handbook 44 — Appendix C, General tables of units of measurement
- UK Weights and Measures Act 1985, Schedule 1 — Definitions of units
- Wikipedia — Fuel economy in automobiles
Reviewed Oct 17, 2026 · test vectors fixtures/units/fuel/mpg-to-l-100km/