Litres to UK Gallons Converter
An imperial gallon is 4.54609 litres, twenty percent larger than a US gallon. Here is the conversion and why mpg figures are not comparable across countries.
Conversions completed
The UK gallon is 20 percent larger
An imperial gallon is defined as 4.54609 litres. A US gallon is 3.78541 litres. The UK gallon is exactly 8 imperial pints of 568.26 mL, while the US gallon is 8 US pints of 473.18 mL. Britain officially moved to litres in 1995 for fuel sales, but gallons still appear in fuel-economy figures and in older equipment specs.
| Volume | Litres | US gallons | UK gallons |
|---|---|---|---|
| 1 litre | 1 L | 0.2642 | 0.2200 |
| 1 US gallon | 3.7854 L | 1 | 0.8327 |
| 1 UK gallon | 4.5461 L | 1.201 | 1 |
| 50 litre tank | 50 L | 13.21 | 11.00 |
| 60 litre tank | 60 L | 15.85 | 13.20 |
Why mpg figures cannot be compared across countries
This is the trap that catches almost everyone importing a car. A British car quoted at 40 mpg is using the imperial gallon, so it burns 4.546 litres over 40 miles. The same fuel economy expressed in US mpg is 33.3, not 40. The car has not changed; the gallon has.
| mpg figure | Which gallon | L/100 km | Converted to the other mpg |
|---|---|---|---|
| 40 mpg | UK imperial | 7.06 | 33.3 US mpg |
| 40 mpg | US | 5.88 | 48.0 UK mpg |
| 50 mpg | UK imperial | 5.65 | 41.6 US mpg |
| 30 mpg | US | 7.84 | 36.0 UK mpg |
Converting in practice
- UK mpg to L/100 km: divide 282.481 by the mpg figure.
- US mpg to L/100 km: divide 235.215 by the mpg figure.
- UK mpg to US mpg: multiply by 0.8327.
- Official UK fuel economy is now quoted in mpg (imperial) and L/100 km side by side, so check which column you are reading.
Related pages
Frequently Asked Questions
How many litres in a UK gallon?
4.54609 litres exactly. A US gallon is 3.78541 litres.
Is 40 mpg the same in the UK and US?
No. 40 UK mpg equals 33.3 US mpg. The imperial gallon is larger, so the same figure represents more fuel per mile.
Do British petrol stations still sell in gallons?
No. Fuel has been sold in litres since 1995, but fuel economy is still often quoted in mpg (imperial).
