Converting Gallons to Liters

Worked Volume Unit Conversion Example Problem

The gallon to liter conversion is a common volume conversion.
The gallon to liter conversion is a common volume conversion. Steve McAlister, Getty Images

This example problem demonstrates how to convert gallons to liters. Gallons and liters are two common units of volume. The liter is the metric volume unit, while the gallon is the English unit. However, the American gallon and the British gallon are not the same! The gallon used in the United States is equal to exactly 231 cubic inches or 3.785411784 liters. The Imperial gallon or UK gallon is equal to approximately 277.42 cubic inches. If you're asked to perform the conversion, make sure you know which country it's for or you won't get the correct answer. This example uses the American gallon, but the set-up for the problem works the same for the Imperial gallon (just using 277.42 instead of 3.785).

Key Takeaways: Gallons to Liters

  • The unit conversion between (American) gallons and liters is 1 gallon = 3.785 liters.
  • British and American gallons are not the same. The American gallon is a smaller unit of volume and has a different conversion factor.
  • There are about four liters per gallon.

Gallons to Liters Problem

What is the volume of a 5 gallon bucket in liters?


1 gallon = 3.785 liters

Set up the conversion so the desired unit will be cancelled out. In this case, we want liters to be the remaining unit.

volume in L = (volume in gal) x (3.785 L/1 gal)

volume in L = (5 x 3.785) L

volume in L = 18.925 L

In other word, there are about 4x more liters when you convert from gallons.


A 5 gallon bucket contains 18.925 liters.

Liters to Gallon Conversion

You can use the same conversion factor to convert liters to gallons or you can use:

1 liter = 0.264 US gallons

To find how many gallons are in 4 liters, for example:

gallons = 4 liters x 0.264 gallons/liter

The liters cancel out, leaving the gallon unit:

4 liters = 1.056 gallons

Keep this in mind: there are about 4 liters per US gallon. So, a half gallon is about 2 liters, while 2 gallons is around 8 liters.

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Your Citation
Helmenstine, Anne Marie, Ph.D. "Converting Gallons to Liters." ThoughtCo, Jul. 18, 2022, Helmenstine, Anne Marie, Ph.D. (2022, July 18). Converting Gallons to Liters. Retrieved from Helmenstine, Anne Marie, Ph.D. "Converting Gallons to Liters." ThoughtCo. (accessed June 10, 2023).