About the Gallons to Liters
This gallons to liters converter handles both kinds of gallon: the US liquid gallon (3.785 L) and the larger UK imperial gallon (4.546 L). Choose which one your number is in, enter the amount, and you get liters, milliliters and the equivalent in the other gallon — so you can see exactly how much a "gallon" differs across the Atlantic.
Use it for fuel tanks and fuel prices, aquarium and pond volumes, water heaters, paint, milk jugs, brewing, or recipes scaled up to bulk quantities. The chart shows common amounts from 1 to 100 gallons in both systems.
Both gallons are defined exactly in liters, so the only rounding is in the decimals shown. If you are unsure which gallon applies, US labels and prices use US gallons; the UK, and older Canadian and Australian sources, use imperial.
With the default inputs, the liters is 3.7854 L. Change any value above to recalculate instantly.
How to use the gallons to liters
- 1Enter the number of gallons.
- 2Choose US gallons or imperial (UK) gallons.
- 3Read the liters, milliliters and the equivalent in the other gallon.
- 4Use the chart to compare both gallon types at a glance.
Formula and method
The US liquid gallon is defined as 231 cubic inches, which is exactly 3.785411784 liters. The imperial gallon used in the UK is defined as exactly 4.54609 liters. Multiply the number of gallons by the right factor to get liters, and by 1,000 more for milliliters.
The equivalent in the other system is liters divided by the other gallon size. Both systems have 4 quarts per gallon, but the quarts are different sizes too.
- L
- Volume in liters
- 3.785411784
- Liters per US liquid gallon (exact)
- 4.54609
- Liters per imperial gallon (exact)
Worked examples
One US gallon of milk
1 × 3.785411784 = 3.785 L. That is only 0.833 of an imperial gallon, because the imperial gallon is larger.
5 imperial gallons (UK jerry can)
5 × 4.54609 = 22.73 L. The same volume is just over 6 US gallons.
15 US gallon fuel tank
15 × 3.785411784 = 56.78 L, which is about 12.5 imperial gallons.
Frequently asked questions
How many liters are in a gallon?+
A US liquid gallon is 3.785 liters and a UK imperial gallon is 4.546 liters. If the source is American, use the US gallon.
Why are US and UK gallons different?+
The US kept the old English wine gallon of 231 cubic inches, while Britain redefined its gallon in 1824 as the volume of 10 pounds of water, which is larger (now fixed at 4.54609 L).
How many liters is 5 gallons?+
5 US gallons is 18.93 liters; 5 imperial gallons is 22.73 liters. A typical water cooler bottle is 5 US gallons (about 19 L).
How do I convert liters back to gallons?+
Divide liters by 3.785411784 for US gallons, or by 4.54609 for imperial gallons. For example, 50 L ÷ 3.785 = 13.2 US gallons.