L/100km to MPG Converter
Convert liters per 100 km to miles per gallon — the European figure into the British one. Results update as you type; exact factors shown.
One liters per 100 km is 282.4809 miles per imperial gallon — see the exact factor, not a rounded rule of thumb.
How the l/100km to mpg converter works
Fuel economy is an inverse quantity: lower L/100 km is better, higher mpg is better. mpg (US) = 235.215 / (L/100 km) because a US gallon is 3.785 L and a mile 1.609 km; mpg (UK) = 282.481 / (L/100 km) with the 4.546 L imperial gallon. UK mpg figures are therefore always 20% higher than US mpg for the same car.
The US uses customary units (US gallon, short ton, °F) in daily life; NIST SP 811 gives the exact SI factors.
Common fuel economy conversions
| From | To | Units |
|---|---|---|
| 3 L/100 km | 94.1603 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 4 L/100 km | 70.6202 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 5 L/100 km | 56.4962 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 6 L/100 km | 47.0802 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 7 L/100 km | 40.3544 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 8 L/100 km | 35.3101 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 9 L/100 km | 31.3868 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 10 L/100 km | 28.2481 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 12 L/100 km | 23.5401 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 15 L/100 km | 18.8321 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 20 L/100 km | 14.124 mpg (UK) | liters per 100 km to miles per imperial gallon |
| 25 L/100 km | 11.2992 mpg (UK) | liters per 100 km to miles per imperial gallon |
Units in this converter and their exact factors
| Unit | Symbol | To L/100 km |
|---|---|---|
| liters per 100 km | L/100 km | x |
| kilometers per liter | km/L | 100÷x |
| miles per imperial gallon | mpg (UK) | 282.480936÷x |
| miles per US gallon | mpg (US) | 235.214583÷x |
FAQFrequently asked questions about fuel economy conversion
What is 7 L/100km in mpg?
About 40 mpg imperial, or 34 mpg US.
Which gallon does this use?
The imperial gallon. The US gallon is smaller, so US mpg numbers are lower for the same car.
Why is the conversion not linear?
Because the two are reciprocals — halving L/100km doubles mpg.
What is a good L/100km?
Under 6 is efficient, 8–10 is typical for a mid-size petrol car, above 12 is thirsty.
How much fuel for a trip?
Multiply L/100km by the distance in km and divide by 100.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Institute of Standards and Technology (NIST) — United States's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.