How to convert miles per gallon to miles per imperial gallon
Formula: mpg (UK) = mpg × 1.20095
Worked example: 30 mpg → 30 × 1.20095 = 36.0285 mpg (UK)
Multiply US mpg by 1.20095 to get UK mpg, because the imperial gallon is larger. A car rated 30 mpg in the US shows about 36 mpg in a British review, with exactly the same consumption.
Miles per gallon to miles per imperial gallon conversion chart
| Miles per gallon (mpg) | Miles per imperial gallon (mpg (UK)) |
|---|---|
| 10 mpg | 12.0095 mpg (UK) |
| 15 mpg | 18.0142 mpg (UK) |
| 18 mpg | 21.6171 mpg (UK) |
| 20 mpg | 24.019 mpg (UK) |
| 22 mpg | 26.4209 mpg (UK) |
| 25 mpg | 30.0237 mpg (UK) |
| 28 mpg | 33.6266 mpg (UK) |
| 30 mpg | 36.0285 mpg (UK) |
| 32 mpg | 38.4304 mpg (UK) |
| 35 mpg | 42.0332 mpg (UK) |
| 40 mpg | 48.038 mpg (UK) |
| 45 mpg | 54.0427 mpg (UK) |
| 50 mpg | 60.0475 mpg (UK) |
| 60 mpg | 72.057 mpg (UK) |
What is a mile per gallon?
Miles per US gallon are the fuel economy unit of US window stickers and EPA ratings. Higher is better. Because it is a distance per volume, savings are not linear: going from 10 to 20 mpg saves far more fuel than going from 30 to 40 mpg.
What is a mile per imperial gallon?
UK mpg use the imperial gallon of 4.546 liters, 20% larger than the US gallon. The same car therefore shows a higher figure in Britain: 40 UK mpg is only about 33 US mpg.