A gallon can be converted into liters based on the type of gallon:

• 1 U.S. gallon (liquid) is equal to approximately 3.785 liters.
• 1 U.S. dry gallon (solid) is about 4.404 liters.
• 1 British or Imperial gallon (used in the UK and some Commonwealth countries) is about 4.546 liters.

The most commonly referenced gallon, the U.S. liquid gallon, equals about 3.785 liters.