US Gallon (gal) Conversions
The US liquid gallon is a unit of volume used mainly in the United States. It is commonly used for fuel, milk, water, paint, and other liquids.
1 US gal = 3.785411784 L
What Is a US Gallon?
A US liquid gallon is defined as exactly 231 cubic inches, which is equal to 3.785411784 litres.
- 1 US gal = 4 US quarts
- 1 US gal = 8 US pints
- 1 US gal = 16 US cups
- 1 US gal = 128 US fluid ounces
The standard symbol for a gallon is gal. When it is important to distinguish it from an imperial gallon, it may be written as US gal.
A Short History of the US Gallon
Gallons were originally used in England to measure products such as wine, beer, and grain, but these gallons were not all the same size.
The modern US liquid gallon developed from the English wine gallon, which was defined as 231 cubic inches. The United States adopted this measurement as its standard liquid gallon in the nineteenth century.
Britain later introduced the larger imperial gallon, so the word “gallon” now refers to different volumes in the US and imperial systems.
US Gallon and Imperial Gallon
A US gallon and an imperial gallon are not interchangeable. The imperial gallon is larger:
- 1 US gallon = 3.785411784 litres
- 1 imperial gallon = 4.54609 litres
Always check which gallon a label, recipe, fuel figure, or conversion uses. Assuming the wrong definition can change the result by roughly 20%.
How to Convert US Gallons
To convert US gallons to another volume unit, first multiply by 0.003785411784 to express the volume in cubic metres. Then divide by the cubic-metre value of the target unit.
Target value = US gallons × 0.003785411784 ÷ target unit factor
Example: Convert 5 US Gallons to Litres
Multiply 5 by 3.785411784:
5 US gal × 3.785411784 = 18.92705892 L
Therefore, 5 US gallons is approximately 18.93 litres.
Common US Gallon Conversions
- 1 US gal = 3.785411784 L
- 1 US gal = 3,785.411784 mL
- 1 US gal = 0.003785411784 m³
- 1 US gal = 3,785.411784 cm³
- 1 US gal = 16 US cups
- 1 US gal = 128 US fl oz
Where US Gallons Are Used
In the United States, petrol is sold by the gallon, and fuel economy is usually shown in miles per gallon. Gallons also appear on containers of milk, bottled water, paint, cleaning products, and other liquids.
Smaller amounts are normally measured in quarts, pints, cups, or fluid ounces, while larger quantities may be expressed in gallons or cubic feet.
US Gallon Conversion Links
Convert US gallons to another volume unit: