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 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
| 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
Common questions
- How many litres are in a gallon?
- A US gallon is 3.785411784 litres. An imperial gallon is larger, at 4.54609 litres.
- Why are there two different gallons?
- The United States kept the British wine gallon as defined in 1707. Britain redefined its own gallon in 1824 as the volume of ten pounds of water. The two have differed ever since.
- How many US gallons is 50 litres?
- 50 litres is 13.21 US gallons, or 11 imperial gallons. That is a typical family car tank.
- Does the gallon difference affect fuel prices?
- Considerably. Fuel at 1.60 per litre works out at 6.06 per US gallon but 7.27 per imperial gallon, so quoting the wrong one misstates the price by about 20 per cent.