How many Oz in a gallon?

1 Gallon


128 Oz

Gallon to Oz (How many Oz in a gallon?)


The gallons to ounces converter is used to convert the volume in gallons (gal) to volume in fluid ounces (fl. Oz). When using the converter, first enter the value in gallons in the blank text field. Press the ‘Convert' button to execute the conversion from gallons to fluid ounces. The conversion result is displayed below the control buttons in fluid ounces. Use the ‘Reset' button when you want to perform a new conversion. It erases all data of the previous calculations from the converter with a single click.


Convert 0.5 gallons to fluid ounces.


The first procedure is to enter the value in gallons (0.5) in the blank text field. Press the ‘Convert' button to initiate the conversion. The result is displayed as;

0.5 Gallon = 64 fluid ounces

This means that there are 64 fluid ounces in 0.5 gallons.

The same procedure is used when converting new values in gallons to get the corresponding results in fluid ounces. 

How many fluid ounces in a gallon?

The volume units' conversion factor of gallons to fluid ounces varied depending on the standard used in the conversion.

1 Gallon [Fluid, US] = 128 Ounces [Fluid, US]

1 Gallon [Dry, US] = 148.946 Ounces [Fluid, US]

1 Gallon [UK] = 160 Ounces [UK]

Therefore, there are 128 US fluid ounces in one US fluid gallon, 148.946 US fluid ounces in one US dry gallon, and 160 imperial ounces in one imperial gallon.

From the smallest to the largest units between gallons and ounces, there are 8 ounces in a cup, 2 cups in a pint, 2 pints in a quart and 4 quarts in a gallon.

Thus; 8 x 2 x 2 x 4 = 128 ounces in a gallon. 


A gallon is a volume unit in the imperial and US customary systems abbreviated as "gal". One US fluid gallon is equal to 231 cubic inches.

A fluid ounce is a volume unit in the US customary and imperial systems abbreviated as "fl. Oz".

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