Fluid Ounces to Gallons Converter

Enter the volume in fluid ounces below to get the value converted to gallons.


Result in Gallons:

Loading content.
1 fl oz = 0.007812 gal

Do you want to convert gallons to fluid ounces?

How to Convert Fluid Ounces to Gallons

To convert a measurement in fluid ounces to a measurement in gallons, divide the volume by the following conversion ratio: 128 fluid ounces/gallon.

Since one gallon is equal to 128 fluid ounces, you can use this simple formula to convert:

gallons = fluid ounces ÷ 128

The volume in gallons is equal to the volume in fluid ounces divided by 128.

For example, here's how to convert 500 fluid ounces to gallons using the formula above.
gallons = (500 fl oz ÷ 128) = 3.90625 gal
conversion scale showing fluid ounces and equivalent gallons volume values

Fluid ounces and gallons are both units used to measure volume. Keep reading to learn more about each unit of measure.

What Is a Fluid Ounce?

The US fluid ounce is a unit of volume equal to 1/16 of a pint or 1/8 of a cup. The fluid ounce is sometimes referred to as just an "ounce" but should not be confused with the unit of weight. One fluid ounce is equal to approximately 29.5735 milliliters, but in nutrition labeling, one fluid ounce is rounded to exactly 30 milliliters.[1]

The fluid ounce is a US customary unit of volume. Fluid ounces can be abbreviated as fl oz, and are also sometimes abbreviated as oz fl. For example, 1 fluid ounce can be written as 1 fl oz or 1 oz fl.

Learn more about fluid ounces.

What Is a Gallon?

The US liquid gallon is a unit of fluid volume equal to four quarts, eight pints, or sixteen cups.[2] The US liquid gallon should not be confused with the US dry gallon or the imperial gallon, which are different units of measure.

The gallon is a US customary unit of volume. Gallons can be abbreviated as gal; for example, 1 gallon can be written as 1 gal.

Learn more about gallons.

Fluid Ounce to Gallon Conversion Table

Table showing various fluid ounce measurements converted to gallons.
Fluid Ounces Gallons
1 fl oz 0.007812 gal
2 fl oz 0.015625 gal
3 fl oz 0.023437 gal
4 fl oz 0.03125 gal
5 fl oz 0.039062 gal
6 fl oz 0.046875 gal
7 fl oz 0.054687 gal
8 fl oz 0.0625 gal
9 fl oz 0.070312 gal
10 fl oz 0.078125 gal
20 fl oz 0.15625 gal
30 fl oz 0.234375 gal
40 fl oz 0.3125 gal
50 fl oz 0.390625 gal
60 fl oz 0.46875 gal
70 fl oz 0.546875 gal
80 fl oz 0.625 gal
90 fl oz 0.703125 gal
100 fl oz 0.78125 gal
200 fl oz 1.5625 gal
300 fl oz 2.3438 gal
400 fl oz 3.125 gal
500 fl oz 3.9063 gal
600 fl oz 4.6875 gal
700 fl oz 5.4688 gal
800 fl oz 6.25 gal
900 fl oz 7.0313 gal
1,000 fl oz 7.8125 gal


  1. U.S. Food & Drug Administration, Guidance for Industry: Guidelines for Determining Metric Equivalents of Household Measures, https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-guidelines-determining-metric-equivalents-household-measures
  2. National Institute of Standards and Technology, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Handbook 44 - 2019 Edition, https://nvlpubs.nist.gov/nistpubs/hb/2019/NIST.HB.44-2019.pdf

More Fluid Ounce & Gallon Conversions