Convert MPG (US) to MPG (UK) (mpg to mpg UK)
1 mile per US gallon (mpg) = 1.200949926 miles per imperial gallon (mpg (UK)). 1 mpg (UK) = 0.8326741846 mpg. Example: 30 mpg = 30 × 1.200949926 = 36.02849777 mpg (UK).
Also searched as miles per US gallon to mpg UK, miles per US gallon in mpg UK, miles per US gallon into miles per imperial gallon, mpg to mpg UK, mpg in miles per imperial gallon, mpg into mile per imperial gallon, mile per US gallon to mile per imperial gallon, mpg to miles per imperial gallon converter and how many miles per imperial gallon in a mile per US gallon.
1 mpg = 1.200949926 mpg (UK)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk mile per US gallon to mile per imperial gallon converter to paste a column from Excel.
How to Convert MPG (US) to MPG (UK)
- 1 mpg = 1.200949926 mpg (UK)
- 1 mpg (UK) = 0.8326741846 mpg
- Example: convert 30 mpg to mpg (UK): 30 mpg = 30 × 1.200949926 mpg (UK) = 36.02849777 mpg (UK)
Formula
mpg (UK) = mpg × 1.200949925505
Derivation from SI units:
- 1 mpg (US) = 1.609344 km ÷ 3.785411784 L = 0.425143707… km/L.
- 1 mpg (UK) = 1.609344 km ÷ 4.54609 L = 0.354006189… km/L.
- 1 mpg = 0.4251437074303 km/L ÷ 0.3540061899346 km/L per mpg (UK) = 1.200949925505 mpg (UK)
Both units are defined exactly, so the factor is exact. MPG (US) definition: mile per US gallon; MPG (UK) definition: mile per imperial gallon.
Worked examples
- A car rated 30 mpg in the US is 36.02849777 mpg (UK) in the UK.
30 mpg × 1.200949926 = 36.02849777 mpg (UK) - A rating of 40 mpg equals 48.03799702 mpg (UK).
40 mpg × 1.200949926 = 48.03799702 mpg (UK)
MPG (US) to MPG (UK) conversion table
| MPG (US) (mpg) | MPG (UK) |
|---|---|
| 15 mpg | 18.01424888 mpg (UK) |
| 20 mpg | 24.01899851 mpg (UK) |
| 25 mpg | 30.02374814 mpg (UK) |
| 30 mpg | 36.02849777 mpg (UK) |
| 35 mpg | 42.03324739 mpg (UK) |
| 40 mpg | 48.03799702 mpg (UK) |
| 45 mpg | 54.04274665 mpg (UK) |
| 50 mpg | 60.04749628 mpg (UK) |
| 60 mpg | 72.05699553 mpg (UK) |
| 100 mpg | 120.0949926 mpg (UK) |
Where it's used
US mpg ratings are converted to UK (imperial) mpg to compare American and British car figures. Multiply by about 1.20095, the ratio of the two gallons.
MPG (US) to other fuel economy units
| Conversion | 1 mpg equals |
|---|---|
| mile per US gallon to mile per imperial gallon | 1.200949926 mpg (UK) |
| mile per US gallon to liter per 100 kilometers | 235.2145833 L/100 km |
| mile per US gallon to kilometer per liter | 0.4251437074 km/L |
Frequently asked questions
Why does the same car get more mpg in the UK?
The imperial gallon is about 20 % larger, so the same car travels further per gallon: 30 US mpg = 36.02849777 mpg (UK).
How many miles per imperial gallon are in 1 mile per US gallon?
1 mpg = 1.200949926 mpg (UK).
How do I convert miles per US gallon to miles per imperial gallon?
Multiply the value in mpg by 1.200949926. For example, 30 mpg × 1.200949926 = 36.02849777 mpg (UK).
Is the mpg to mpg (UK) conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "mile per gallon (U.S.)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "mile per gallon (U.K.)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert MPG (US) to MPG (UK) (mpg to mpg UK). Retrieved October 25, 2026, from https://scientificconverters.com/fuel-economy/miles-per-gallon-to-miles-per-gallon-uk/
IEEE
Scientific Converters, "Convert MPG (US) to MPG (UK) (mpg to mpg UK)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/fuel-economy/miles-per-gallon-to-miles-per-gallon-uk/