Gal/100 Mi (US) to MPG (UK) (gal/100 mi to mpg (UK))
1 gallon (US) per 100 miles equals 120.0949926 miles per gallon (imperial).
How to convert gallons (US) per 100 miles to miles per gallon (imperial)
Converting gallons (US) per 100 miles to miles per gallon (imperial) is not a simple multiplication, so use the formula below.
miles per gallon (imperial) = 120.0949926 ÷ gallons (US) per 100 miles
Example: 10 gallons (US) per 100 miles = 12.00949926 miles per gallon (imperial).
Miles per gallon rises as a car gets more efficient, while liters per 100 km falls. The conversion between them is a reciprocal (for US mpg: L/100 km = 235.215 ÷ mpg).
About these units
Gallon (US) Per 100 Miles (gal/100 mi)
US gallons used per 100 miles. Proposed in the US as a more intuitive way to compare efficiency than miles per gallon.
Gallons per 100 miles flips the familiar miles-per-gallon figure upside down, so that lower numbers mean a more efficient vehicle. New US window stickers have shown it next to mpg since the EPA's 2011 labeling rule, which became mandatory for model year 2013. The label estimates how much fuel or electricity a car needs to cover 100 miles.
The reason is the so-called MPG illusion. Fuel use per mile is the reciprocal of mpg, so equal gains in mpg do not save equal fuel. Lifting a car from 10 to 20 mpg doubles its efficiency, while lifting another from 50 to 60 mpg improves it by only 20 percent, even though each gains 10 mpg.
The unit is the same measure as liters per 100 kilometers used in much of the world. One gallon per 100 miles equals about 2.352 L per 100 km, and the converter stores it as kilometers per liter, so a value x gal/100 mi corresponds to 42.514 divided by x km/L. That is also why a reading of zero has no meaning.
1 gallon (US) per 100 miles = 42.51437074 kilometers per liter (approximately).
Sources: Wikipedia: Fuel economy in automobiles; Wikipedia: Fuel efficiency
Mile Per Gallon (imperial) (mpg (UK))
Miles traveled on one imperial gallon (4.546 L). The UK still quotes fuel economy this way, so UK mpg figures are about 20% higher than US ones for the same car.
Britain's gallon is a child of the 1824 reform. It was originally defined as the volume of 10 pounds of distilled water at 62 degrees Fahrenheit, taken as 277.274 cubic inches; an 1889 Order in Council changed the figure to 277.463 cubic inches, and in 1976 the UK adopted the metric definition of exactly 4.54609 litres, after Canada had done so. The gallon used in the United States comes from a different, older wine measure, so the two differ by about 20 percent.
One imperial gallon is about 1.2 US gallons, which means that a car rated at 40 mpg in the UK delivers only about 33 mpg on the US scale. Miles per imperial gallon is still the UK's main fuel-economy unit even though petrol is sold by the litre and selling goods by the imperial gallon is no longer legal in Britain. Some Caribbean territories, such as the Cayman Islands and Grenada, still sell petrol by the imperial gallon, while the UAE, Guyana and Myanmar switched to litres in 2010, 2013 and 2014. When a figure says only mpg, check which gallon is meant.
1 mile per gallon (imperial) = 0.3540061899 kilometers per liter (approximately).
Sources: Wikipedia: Imperial gallon; Wikipedia: Fuel economy in automobiles
Related conversions
- MPG (UK) to gal/100 mi (US) (reverse)
- Gal/100 mi (US) to km/L
- Gal/100 mi (US) to MPG (US)
- Gal/100 mi (US) to L/100 km
- Km/L to MPG (UK)
- MPG (US) to MPG (UK)
- L/100 km to MPG (UK)
- Mi/L to MPG (UK)
- Gal/100 mi (UK) to MPG (UK)
- L/mil to MPG (UK)
See all fuel economy units.