Imperial Gallons to Litres Converter
Convert UK Imperial gallons to litres. This page labels Imperial gallons separately because they differ from US liquid gallons.
Enter a zero or positive amount. Decimal values are supported. Only the displayed result is rounded.
Reference: NIST Guide to the SI, Appendix B.9 (volume conversion factors). The displayed result is rounded; it is a unit conversion, not a measurement of water need.
Formula
L = Imp gal × 4.54609
Example: 1 Imperial gal is 4.54609 L.
About these units
An Imperial gallon is 4.54609 L; a US liquid gallon is about 3.785412 L. Choose the unit printed on your source rather than assuming that “gallon” means the same volume everywhere.
Everyday conversion examples
Choose this converter only when the source quantity is specifically an Imperial gallon, commonly used in UK contexts. It should not be substituted for a US gallon conversion.
| Imperial gallons | Litres |
|---|---|
| 0.5 | 2.273 |
| 1 | 4.546 |
| 2 | 9.092 |
| 5 | 22.73 |
Examples are rounded for readability. Use the calculator above for another amount; it keeps the conversion factor until the final display.
How is an Imperial gallon different from a US gallon?
An Imperial gallon is 4.54609 L, compared with about 3.785412 L for a US liquid gallon—roughly 20% more volume.
What if my label only says “gallon”?
Check the product’s country or source documentation. The unit name alone may not identify which gallon standard was intended.
Source
Conversion factors are based on customary and metric volume relationships documented by the National Institute of Standards and Technology (NIST), Guide to the SI, Appendix B.9. NIST reports rounded factors; this page displays a rounded result.