Calculator
MPG to L/100km Converter
Convert fuel economy between US MPG, UK (imperial) MPG, litres per 100 km and km per litre, with the formulas and a quick conversion table.
7.8 L/100 km — that is 30.0 mpg in the US and 36.0 mpg in the UK.
Why MPG and L/100 km don't convert in a straight line
Miles per gallon measures distance per fuel: higher is better. Litres per 100 km measures fuel per distance: lower is better. One is the reciprocal of the other, so the conversion is a division, not a multiplication — going from 15 to 20 mpg saves far more fuel than going from 40 to 45 mpg.
The gallon is different too: a US gallon is 3.785 L, an imperial (UK) gallon 4.546 L. The same car therefore shows a 20% higher MPG figure in the UK than in the US.
Formulas
- L/100 km = 235.215 ÷ mpg (US) · mpg (US) = 235.215 ÷ L/100 km
- L/100 km = 282.481 ÷ mpg (UK) · mpg (UK) = 282.481 ÷ L/100 km
- km/L = 100 ÷ L/100 km · mpg (UK) = mpg (US) × 1.20095
Conversion table
| mpg (US) | L/100 km | mpg (UK) | km/L |
|---|---|---|---|
| 15 | 15.7 | 18.0 | 6.4 |
| 20 | 11.8 | 24.0 | 8.5 |
| 25 | 9.4 | 30.0 | 10.6 |
| 30 | 7.8 | 36.0 | 12.8 |
| 35 | 6.7 | 42.0 | 14.9 |
| 40 | 5.9 | 48.0 | 17.0 |
| 45 | 5.2 | 54.0 | 19.1 |
| 50 | 4.7 | 60.0 | 21.3 |
| 60 | 3.9 | 72.1 | 25.5 |
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