Mile Per Gallon (US) (mpg (US))

Miles traveled on one US gallon of fuel. The standard fuel-economy unit in the United States; higher is better.

1 mile per gallon (US) = 0.4251437074 kilometers per liter (approximately).

About the mile per gallon (US)

American fuel economy became a matter of policy in the 1970s. After the 1973 Arab oil embargo, Congress enacted the Corporate Average Fuel Economy rules in 1975, setting a sales-weighted average for each manufacturer's cars and light trucks. Fleet economy had been sliding until 1973, reaching a low of about 13.4 mpg, then rose as fuel costs rose: about 17 mpg in 1978, 22 in 1982, and about 25.4 mpg for the average new vehicle in the 2020 model year. Earlier still, the Mobil Economy Run (1936 to 1968) tested real-world mileage on a coast-to-coast route.

The US gallon is legally 231 cubic inches, or 3.785411784 litres. It descends from the English wine gallon, redefined as 231 cubic inches in 1706 under Queen Anne and adopted as the US standard in 1836. It is about 17 percent smaller than the imperial gallon, so US mpg figures look lower than British ones for the same car. Mpg has a quirk known as the MPG illusion: going from 10 to 20 mpg halves fuel use, but going from 50 to 60 mpg saves far less, even though both are 10 mpg gains. For that reason the EPA label also shows gallons per 100 miles.

Sources: Wikipedia: Fuel economy in automobiles; Wikipedia: Imperial gallon; fueleconomy.gov: Learn more about the gasoline label

Mile Per Gallon (US) conversion chart

10 miles per gallon (US) expressed in every other fuel economy unit:

Unit	10 miles per gallon (US)
Km/L	4.251437074
MPG (UK)	12.00949926
L/100 Km	23.52145833
Mi/L	2.641720524
Gal/100 Mi (US)	10
Gal/100 Mi (UK)	8.326741846
L/mil	2.352145833

More US customary units

All US customary units

Browse all fuel economy units.