Liter
 A liter (symbol: L) is a unit of volume that is accepted for use with the International System of Units (SI) but is technically not an SI unit. One liter is equal to 1 cubic decimeter (dm3), 1,000 cubic centimeters (cm3), or 1/1,000 cubic meters (m3).
Gallon (US)
Both the US customary and imperial systems of measurement use the term "gallon" to refer to a volumetric unit of liquid capacity. 231 cubic inches make to a US gallon (3.785 liters). The imperial gallon, on the other hand, is defined as 4.54609 liters and is used in some Caribbean countries, the United Kingdom, and Canada. Four quarts are divided into one gallon in both systems. Then, quarts are divided into two pints, and pints into two cups. Two gills make up a cup, so one gallon is equivalent to four quarts, eight pints, sixteen cups, or thirty-two gills. A US gallon is divided into four fluid ounces, while an imperial gallon is divided into five, further highlighting the differences between the two measurements.

Have you ever needed or wanted to convert liters to gallons for anything? It's not difficult at all:
First, you need to know how many gallons are in a liter. There are 0.264 gallons per liter.
Let's say you need to convert 10 liters to gallons. Just multiply the amount you have (10 liters) by the conversion factor: 10 liters multiplied by 0.264 gallons per liter equals 2.64 gallons. So 10 liters equals 2.64 gallons.
Find out more easily here:
https://www.calculatorful.com/liters-to-gallons