What this converter does
This converter switches between litres per 100 km and US miles per gallon — the two main ways of stating fuel economy. Type an L/100km figure and read the MPG, or swap the arrow to go the other way. The relationship is inverse, so a lower L/100km means a higher MPG.
The constant is 235.215 for US gallons: MPG = 235.215 ÷ L/100km. UK gallons use 282.481 instead. For distance and volume on their own, a length or volume converter is the better tool.
The units it covers
These measure the same thing two ways — one is fuel per distance, the other distance per fuel, so they are inverse.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Litres per 100 km | L/100km | lower = better | Metric fuel consumption |
| Miles per gallon (US) | MPG | higher = better | US fuel economy |
| Constant (US) | 235.215 | MPG × L/100km | Links the two scales |
| Constant (UK) | 282.481 | imperial gallon | For UK MPG instead |
The formula
The two are inversely related through a fixed constant:
MPG = 235.215 ÷ (L/100km) (and L/100km = 235.215 ÷ MPG)Where:
- L/100km = litres used per 100 kilometres
- MPG = US miles per gallon
- 235.215 = the US-gallon conversion constant
Worked example
A car uses 8 L/100km. Find its US MPG.
MPG = 235.215 ÷ (L/100km)235.215 ÷ 8 = 29.4 MPGSo 8 L/100km is about 29.4 US MPG — a typical economy figure.
The units in this example
Metric fuel consumption — litres burned per 100 km. Lower is better, the opposite sense to MPG.
- 5 L/100km ≈ 47.0 MPG
- 8 L/100km ≈ 29.4 MPG
- 10 L/100km ≈ 23.5 MPG
- L/100km = 235.215 ÷ MPG
US fuel economy — miles travelled per US gallon. Higher is better. It is inversely related to litres per 100 km.
- 20 MPG ≈ 11.76 L/100km
- 30 MPG ≈ 7.84 L/100km
- 40 MPG ≈ 5.88 L/100km
- MPG = 235.215 ÷ L/100km