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العربيةFuel economy converter — l/100 km, MPG and km/l
Fuel economy is the awkward one: European figures count fuel per distance, American ones count distance per fuel, so the two run in opposite directions and cannot be scaled.
How to use it
- 1
Pick the scale your number is written in — the chips above the input.
- 2
Type the value. Decimals and negative numbers are fine, and a comma works as a decimal point.
- 3
Read every other scale on the right. Click any result to copy it.
Exact conversion factors
These are the definitions the calculator uses. Nothing here is rounded for convenience — where a value is exact by definition, it says so.
- MPG (US) = 235.2145833 ÷ (l/100 km) — divide, never multiply
- MPG (UK) = 282.4809363 ÷ (l/100 km) · km/l = 100 ÷ (l/100 km)
- 5 l/100 km = 47.04 MPG (US) = 20 km/l
- 8 l/100 km = 29.40 MPG (US) = 35.31 MPG (UK) = 12.5 km/l
- 1 MPG (UK) = 1.20095 MPG (US)
MPG (US) = 235.2145833 ÷ (l/100 km) · MPG (UK) = 282.4809363 ÷ (l/100 km) · km/l = 100 ÷ (l/100 km)Fuel economy conversion table — every unit
One of each unit, converted into the three units people ask for most.
| l/100 km | MPG (US) | km/l |
|---|---|---|
| 4 l/100 km | 58.8036 MPG (US) | 25 km/l |
| 5 l/100 km | 47.0429 MPG (US) | 20 km/l |
| 6 l/100 km | 39.2024 MPG (US) | 16.6667 km/l |
| 7 l/100 km | 33.6021 MPG (US) | 14.2857 km/l |
| 8 l/100 km | 29.4018 MPG (US) | 12.5 km/l |
| 10 l/100 km | 23.5215 MPG (US) | 10 km/l |
| 12 l/100 km | 19.6012 MPG (US) | 8.33333 km/l |
| 15 l/100 km | 15.681 MPG (US) | 6.66667 km/l |
How this converter works
Because the relationship is inverse rather than proportional, you cannot convert by multiplying. A car at 8 l/100 km does 29.4 MPG (US); halving consumption to 4 l/100 km doubles the figure to 58.8 MPG. Enter one value and this page inverts it correctly for every other unit.
Watch the two gallons as well. The same car is 29.4 MPG in American figures and 35.3 MPG in British ones, purely because an imperial gallon is larger. Both are on the page so a brochure comparison across markets stays honest.
Notes and abbreviations
- MPG (US) = 235.215 ÷ (l/100 km)
- MPG (UK) = 282.481 ÷ (l/100 km)
- km/l = 100 ÷ (l/100 km)
- Lower l/100 km is better; higher MPG is better
Questions
What is 30 MPG in litres per 100 km?
7.84 l/100 km if that is a US gallon, or 9.42 l/100 km if it is imperial.
Why can I not just multiply by a constant?
The two families are reciprocals. Multiplying works only within a family — between them you divide into a constant.
What is a good figure for a modern petrol car?
Around 6 to 8 l/100 km in mixed driving, which is 29 to 39 MPG (US).