mpg to L/100 km
Short answer
Divide 235.2 by the mpg (US gallons) to get litres per 100 km: 30 mpg = 7.84 L/100 km. For imperial gallons divide 282.5 instead: 30 UK mpg = 9.416 L/100 km.
US and imperial mpg
| mpg | L/100 km (US gal) | L/100 km (UK gal) | km/L |
|---|---|---|---|
| 10 | 23.52 L/100 km | 28.25 L/100 km | 4.251 km/L |
| 15 | 15.68 L/100 km | 18.83 L/100 km | 6.377 km/L |
| 20 | 11.76 L/100 km | 14.12 L/100 km | 8.503 km/L |
| 25 | 9.409 L/100 km | 11.3 L/100 km | 10.63 km/L |
| 30 | 7.84 L/100 km | 9.416 L/100 km | 12.75 km/L |
| 35 | 6.72 L/100 km | 8.071 L/100 km | 14.88 km/L |
| 40 | 5.88 L/100 km | 7.062 L/100 km | 17.01 km/L |
| 45 | 5.227 L/100 km | 6.277 L/100 km | 19.13 km/L |
| 50 | 4.704 L/100 km | 5.65 L/100 km | 21.26 km/L |
| 60 | 3.92 L/100 km | 4.708 L/100 km | 25.51 km/L |
L/100 km to mpg
| L/100 km | US mpg | UK mpg |
|---|---|---|
| 3 | 78.4 mpg | 94.16 mpg (imp) |
| 4 | 58.8 mpg | 70.62 mpg (imp) |
| 5 | 47.04 mpg | 56.5 mpg (imp) |
| 6 | 39.2 mpg | 47.08 mpg (imp) |
| 7 | 33.6 mpg | 40.35 mpg (imp) |
| 8 | 29.4 mpg | 35.31 mpg (imp) |
| 10 | 23.52 mpg | 28.25 mpg (imp) |
| 12 | 19.6 mpg | 23.54 mpg (imp) |
| 15 | 15.68 mpg | 18.83 mpg (imp) |
Questions
Because the units are turned over: more mpg is better, more L/100 km is worse. Converting means dividing a constant by the number, so the steps in the table are uneven.