Unit converter
UK MPG to litres per 100 kilometres.
Convert mpg (UK) to L/100 km and L/100 km to mpg (UK). Type in either box and the other follows. These run in opposite directions: more miles per gallon means fewer litres per 100 km, so this is not a multiplication.
| mpg (UK) | L/100 km |
|---|---|
| 20 mpg (UK) | 14.124 L/100 km |
| 25 mpg (UK) | 11.2992 L/100 km |
| 30 mpg (UK) | 9.41603 L/100 km |
| 35 mpg (UK) | 8.07088 L/100 km |
| 40 mpg (UK) | 7.06202 L/100 km |
| 45 mpg (UK) | 6.27735 L/100 km |
| 50 mpg (UK) | 5.64962 L/100 km |
| 55 mpg (UK) | 5.13602 L/100 km |
| 60 mpg (UK) | 4.70802 L/100 km |
| 70 mpg (UK) | 4.03544 L/100 km |
| 80 mpg (UK) | 3.53101 L/100 km |
- mpg (UK) and L/100 km are reciprocals of one another: as one rises the other falls.
Definitions
- Miles per imperial gallon measures economy: higher is better. UK brochures use it, and the imperial gallon is 4.546 09 L.
- Litres per 100 km measures consumption: lower is better. It is the figure EU and UK official documents lead with.
- This conversion is exact by definition. mpg (UK) × L/100 km = 282.4809363.
- Fuel economy is reciprocal: more miles per gallon is less fuel per 100 km. A US gallon is smaller than an imperial gallon, so US mpg and UK mpg are different numbers for the same car.
How it works
These two units run in opposite directions, so this is a division rather than a multiplication. Doubling one does not double the other; it halves it.
The value passes through L/100 km, the unit every other fuel economy unit on the site is defined against, rather than a number written into this page on its own. That is why the figure here, the figure in the table above and the general fuel economy converter always agree.
Display precision limits significant figures rather than decimal places, which matters here because a reciprocal magnifies rounding: a figure trimmed at one end of the scale moves further at the other. Only the display is rounded. The editable box always holds a plain number at full working precision, so you can carry on from either side.
Common questions this answers: what 45 mpg (UK) is in litres per 100 km (6.27735 L/100 km), what halving it does (12.5547 L/100 km, not half of 6.27735), and which way round the units run — a higher mpg (UK) always means a lower L/100 km.
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