# Litres and gallons converter Enter a volume in any of the three units and see all three at once. One US gallon is 3.785411784 litres and one imperial gallon is 4.54609 litres, so an imperial gallon is about 20 per cent larger. ## There are two different gallons This is the single most common source of error in fuel arithmetic, so the calculator always shows both. ``` 1 US gallon = 3.785411784 litres exactly 1 imperial gallon = 4.54609 litres exactly 1 litre = 0.264172 US gallons = 0.219969 imperial gallons ``` An imperial gallon is about 20 per cent larger than a US gallon. The difference is old: the US kept the British wine gallon of 1707, while Britain redefined its gallon in 1824 as the volume of ten pounds of water. The two have never agreed since. ## Common tank sizes Typical fuel tank capacities in all three units. | Litres | US gal | Imp gal | |---|---|---| | 30 | 7.93 | 6.60 | | 40 | 10.57 | 8.80 | | 50 | 13.21 | 11.00 | | 60 | 15.85 | 13.20 | | 70 | 18.49 | 15.40 | | 80 | 21.13 | 17.60 | | 100 | 26.42 | 22.00 | ## Why this matters for fuel prices Comparing a price per litre with a price per gallon is meaningless until you know which gallon. Fuel at 1.60 per litre is 6.06 per US gallon but 7.27 per imperial gallon. Quoting the wrong one makes a country look 20 per cent cheaper or dearer than it is. The same trap applies to fuel economy figures, which is why the economy converter shows US and imperial MPG side by side rather than choosing one. ## A rough check Four litres is a bit more than a US gallon and a bit less than an imperial one. If a number needs to be right, use the calculator; if you just need to know whether a tank is big, dividing litres by four is close enough. ## Next steps - [see how the two gallons affect MPG figures](https://www.kilometer-mileage.com/fuel-economy-converter.html) - [use a tank volume to measure fuel economy](https://www.kilometer-mileage.com/mileage-calculator.html) - [price a tank of fuel](https://www.kilometer-mileage.com/fuel-cost-calculator.html) ## Common questions