What is the difference between US and imperial gallons?

An imperial gallon is about 20% larger than a US gallon: 4.546 litres versus 3.785 litres. Recipes and fuel figures can differ significantly depending on which one is used.

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Volume

Gallon Calculator

Convert US gallons, imperial gallons, litres, quarts, pints, cups, and fluid ounces instantly, with a full equivalents table and comparison chart.

Result

3.79 L

Equivalent volume

Your value in US gallons, litres, and quarts.

How it works

The gallon comes in two common sizes: the US gallon (3.785 L) and the larger imperial gallon (4.546 L). This tool converts either against litres and the smaller US units.

1 US gallon = 3.78541 L = 4 quarts = 16 cups
1 imperial gallon = 4.54609 L ≈ 1.201 US gallons

Worked example

One US gallon equals 3.79 litres; the same number of imperial gallons would be 4.55 litres.

Frequently asked questions

How many litres are in a US gallon?

3.78541 L. An imperial gallon is 4.54609 L.

US vs imperial gallon?

The imperial gallon is about 20% larger than the US gallon.