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Fuel economy converter
Miles per gallon, kilometres per litre and litres per 100 km — two of which run backwards from the third. 5 units, converted from one table of exact factors.
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Worth knowing. Litres per 100 km runs backwards from the other two: a smaller number is a better car. And a US gallon is a fifth smaller than an imperial one, so the same car is quoted at about 20% more mpg in Britain than in America.
1 mile per gallon (US) in every other fuel economy unit
Computed by the same engine that runs the converter above, so these can never drift apart from it.
| From | Equals | Unit |
|---|---|---|
| 1 mile per gallon (US) | 0.42514371 | kilometer per liter (km/L) |
| 1 mile per gallon (US) | 1.2009499 | mile per gallon (imperial) (mpg (imp)) |
| 1 mile per gallon (US) | 235.21458 | liter per 100 km (L/100km) |
| 1 mile per gallon (US) | 0.26417205 | mile per liter (mi/L) |
What each unit actually is
Most converters give you a number and stop. Where a figure is exact by definition we say so, and where it is an average or shifts with conditions we say that too — that is usually the thing you needed to know.
| Unit | Symbol | What it actually is |
|---|---|---|
| kilometer per liter | km/L | Distance per fuel. Bigger is better. |
| mile per gallon (US) | mpg | The US gallon is 3.785 L, so US mpg is about 20% lower than the same car measured in imperial mpg. |
| mile per gallon (imperial) | mpg (imp) | The imperial gallon is 4.546 L. UK figures use this one. |
| liter per 100 km | L/100km | Fuel per distance — it runs the other way, so smaller is better. 100 divided by km/L. |
| mile per liter | mi/L | Rarely quoted, but it falls out of the same table. |