Convert US Gallon to Fluid Ounce (US)

What is a US Gallon to Fluid Ounce (US) conversion?

One us gallon (gal (US)) is equal to 128 fluid ounce (us) (fl oz). This relationship is fixed by international measurement standards and does not change. To convert any number of us gallon to fluid ounce (us), multiply your value by 128; to go the other way, divide by 128.

How to convert US Gallon to Fluid Ounce (US)

The conversion formula is: 1 gal (US) = 128 fl oz. Enter any value into the converter above and the result updates instantly. The formula is also shown alongside the answer so you can check the working or use it in your own calculations.

Where is this conversion used?

Volume conversions appear in cooking, chemistry, medicine, fuel measurement, and plumbing. The metric system uses litres and millilitres; the imperial system uses pints, gallons, and fluid ounces — and US and UK gallons differ from one another. Pharmacists, bartenders, chemists, plumbers, and fuel engineers routinely convert volumes. Note that a US gallon (3.785 L) and a UK/Imperial gallon (4.546 L) are not the same — always confirm which gallon is intended.

Helpful tip

A standard wine bottle holds 750 mL (0.75 L). A US pint of beer is 473 mL, while a UK pint is 568 mL — nearly 20% larger.