Gallons to Liters Converter
Convert gallons to liters instantly. Works for US and Imperial gallons in both directions, with the exact conversion factors, worked examples and a quick reference chart.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Gallons to Liters Converter Works
This tool converts gallons into liters (and back), supporting both the US gallon and the Imperial (UK) gallon. Choose a direction, type a value, and the result appears instantly with the exact factor displayed.
The Formula
Liters = US gallons × 3.785411784 Liters = Imperial gallons × 4.54609
A US gallon equals exactly 231 cubic inches, which converts to 3.785411784 liters. The Imperial gallon is defined as 4.54609 liters. To reverse the conversion, divide liters by the same factor.
Worked Example
Convert 5 US gallons to liters:
- 5 × 3.785411784 = 18.927 liters
Convert 5 Imperial gallons to liters:
- 5 × 4.54609 = 22.730 liters
The same “5 gallons” produces almost 4 extra liters when it is Imperial rather than US, which matters for fuel tanks and recipes.
US vs Imperial Reference
| Gallons | US → liters | Imperial → liters |
|---|---|---|
| 1 | 3.785 | 4.546 |
| 2 | 7.571 | 9.092 |
| 5 | 18.927 | 22.730 |
| 10 | 37.854 | 45.461 |
| 16 | 60.567 | 72.737 |
Practical Tips
When converting fuel tank sizes, US car specs use US gallons and UK specs use Imperial gallons, so a “12-gallon tank” is not the same volume on both sides of the Atlantic. For cooking and chemistry, US recipes use US gallons. When in doubt, convert to liters first, since the liter is unambiguous worldwide.
Frequently asked questions
How many liters are in a gallon?+
One US gallon is exactly 3.785411784 liters, and one Imperial (UK) gallon is 4.54609 liters. Always confirm which gallon you mean, because the two differ by about 20%.
How do I convert gallons to liters?+
Multiply US gallons by 3.785411784, or multiply Imperial gallons by 4.54609. For example, 5 US gallons × 3.785411784 = 18.927 liters.
How many liters is 5 gallons?+
5 US gallons equal about 18.927 liters, and 5 Imperial gallons equal about 22.730 liters. Multiply by 3.785411784 for US gallons or 4.54609 for Imperial gallons.
Why are US and Imperial gallons different?+
The US gallon is defined as 231 cubic inches (3.785 L), while the Imperial gallon was based on 10 pounds of water (4.546 L). They are separate historical standards, so an Imperial gallon is about 20% larger.
How many liters is a 16-gallon tank?+
A 16 US gallon tank holds about 60.6 liters, while a 16 Imperial gallon tank holds about 72.7 liters. Multiply the gallon figure by the matching factor to get liters.