Imperial Gallons to Liters
Convert UK gallons to litres. The imperial gallon is 4.54609 litres exactly, a fifth larger than the US gallon it is often confused with.
L = imperial gal × 4.54609
NIST SP 811 (2008), Appendix B.8 — gallon [Canadian and U.K. (Imperial)] (gal) to liter (L) = 4.546 09 E+00
There are two gallons in common use and they are not close. The imperial gallon, used in the UK and Canada, is 4.54609 litres. The US gallon is 3.785412. That is a difference of about a fifth, which is why fuel economy figures quoted in miles per gallon are not comparable across the Atlantic without saying which gallon was meant. This page uses the imperial one, and says so in the result rather than leaving you to guess.
How it is calculated
L = imperial gal × 4.54609
The imperial gallon has been defined as exactly 4.54609 litres since 1985, when the UK redefined it in metric terms. Before that it was the volume of ten pounds of water at a specified temperature, which is the sort of definition that moves.
Common values
| imperial gallons | liters |
|---|---|
| 1 | 4.54609 |
| 2 | 9.09218 |
| 5 | 22.73045 |
| 10 | 45.4609 |
| 12 | 54.55308 |
| 15 | 68.19135 |
| 20 | 90.9218 |
| 25 | 113.65225 |
| 50 | 227.3045 |
| 100 | 454.609 |
Questions people ask
- How much bigger is an imperial gallon than a US one?
- About 20 percent. An imperial gallon is 4.54609 litres against 3.785412 for the US gallon, so five US gallons are roughly four imperial ones.
- Why does UK fuel economy look better than US?
- Partly because the gallon is bigger. A car doing 40 miles per imperial gallon does about 33 to the US gallon, and neither figure is wrong — they answer different questions.
- Is the imperial gallon still legal for trade?
- In the UK it survives for road fuel economy figures and for draught beer and cider by the pint, which is an eighth of a gallon. Fuel itself is sold in litres.
- What about the imperial pint?
- It is 568.26125 millilitres, an eighth of the imperial gallon. The US pint is 473 millilitres, which is the other half of why a recipe crossing the Atlantic goes wrong.
Related tools
Gallons to Liters
Convert US gallons to liters in your browser, with a warning about the UK gallon, which is a fifth larger.
Liters to Gallons
Convert liters to US or imperial gallons. The two gallons differ by about twenty percent, so this converter keeps them as separate units rather than guessing.
Quarts to Liters
Convert US quarts to liters in your browser. A quart is 0.946 liters, which is why it gets mistaken for one.
Found a problem, or want more?
A number that disagrees with its source is a defect, not a rounding preference.
What did you enter, what did the tool show, and what did you expect instead? If you have a source that disagrees with ours, a link to it is the most useful thing you can send.
Opens your mail app with the page and tool already filled in.