Gallon to Liter Conversion Example Problem

Wine barrels
Credit: Daniel Vogel/

This example problem illustrates the steps to convert from gallon to liter. This problem is a common homework conversion to help students move from one system of measurement to another.

In this case, the liter is an SI unit of volume and the gallon appears in two different forms: the English Imperial unit and US customary units. The English gallon is 20% larger than the US gallon or 1 Imperial gallon = 1.20 US gallons. This particular example problem uses the US gallon, but the technique is the same.

Gallon to Liter Example Problem

Question: A standard barrel of wine holds 60 gallons. How many liters of wine can this barrel hold?

Solution: The first step is finding the conversion factor between gallons and liters.

1 gallon = 3.785 liters

We have 60 gallons and want liters so we have the ratio

Gallon to Liter Example math step #1

Solve for X Liters and get

Gallon to Liter Example math step #2

Note the gallon unit cancels out.

Gallon to Liter Example math step #3

X Liters = 60 ⋅ 3.785 L
X Liters = 227.1 L

Answer: A standard barrel of wine can hold 227.1 Liters of wine.

Liter to Gallon Example Problem

Question: A common volume for a kitchen trash can is 50 liters. How many gallons of trash can this hold?

Solution: The conversion is the same as above, so we can set the ratio in the same way as the previous example.

Liter to Gallon Example math step #1

Solve for X gallons

Liter to Gallon Example math step #2

This time, the liters unit cancels out.

Liter to Gallon Example math step #3

X gallons = 15.85 gallons

Answer: A 50-liter trash can holds 15.85 gallons of trash.

These examples show how to convert US gallons to liters and back again. If you need to convert Imperial gallons to liters, follow the same steps and use the conversion factor:

1 Imperial UK gallon = 4.54609 liters.