Convert Gallons to Fluid Ounces

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

Results in Fluid Ounces:
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1 gallon = 128 fl oz

How to Convert Gallons to Fluid Ounces

To convert a gallon measurement to a fluid ounce measurement, multiply the beer volume by the conversion ratio. One gallon is equal to 128 fluid ounces, so use this simple formula to convert:

fluid ounces = gallons × 128

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

For example, here's how to convert 5 gallons to fluid ounces using the formula above.
5 gallons = (5 × 128) = 640 fl oz

Gallons and fluid ounces are both units used to measure beer volume. Keep reading to learn more about each unit of measure.


The US gallon is a standard size equivalent to 128 fl. oz. of beer.

The gallon is a US customary unit of beer volume.

Fluid Ounces

In the US, beer is often measured by the fluid ounce, which is the basis for other units of beer volume measure. The standard US bottle of beer contains 12 fluid ounces.

The fluid ounce is a US customary unit of beer volume. Fluid ounces can be abbreviated as fl oz, for example 1 fluid ounce can be written as 1 fl oz.

Gallon Measurements and Equivalent Fluid Ounce Conversions

Common gallon values converted to the equivalent fluid ounce value
Gallons Fluid Ounces
1 128 fl oz
2 256 fl oz
3 384 fl oz
4 512 fl oz
5 640 fl oz
6 768 fl oz
7 896 fl oz
8 1,024 fl oz
9 1,152 fl oz
10 1,280 fl oz
11 1,408 fl oz
12 1,536 fl oz
13 1,664 fl oz
14 1,792 fl oz
15 1,920 fl oz
16 2,048 fl oz
17 2,176 fl oz
18 2,304 fl oz
19 2,432 fl oz
20 2,560 fl oz
21 2,688 fl oz
22 2,816 fl oz
23 2,944 fl oz
24 3,072 fl oz
25 3,200 fl oz
26 3,328 fl oz
27 3,456 fl oz
28 3,584 fl oz
29 3,712 fl oz
30 3,840 fl oz
31 3,968 fl oz
32 4,096 fl oz
33 4,224 fl oz
34 4,352 fl oz
35 4,480 fl oz
36 4,608 fl oz
37 4,736 fl oz
38 4,864 fl oz
39 4,992 fl oz
40 5,120 fl oz

More Gallon Beer Volume Conversions

Convert to Beer Barrels
1 gallon is equal to 0.032258 beer barrels
Convert to Beers
1 gallon is equal to 10.666667 beers
Convert to Bombers
1 gallon is equal to 5.818182 bombers
Convert to Cases
1 gallon is equal to 0.444444 cases
Convert to Forties
1 gallon is equal to 3.2 forties
Convert to Growlers
1 gallon is equal to 2 growlers
Convert to Half Barrel Kegs
1 gallon is equal to 0.064516 half barrel kegs
Convert to Quarter Barrel Kegs
1 gallon is equal to 0.129032 quarter barrel kegs
Convert to Liters
1 gallon is equal to 3.785414 liters
Convert to Pints
1 gallon is equal to 8 pints
Convert to Quarts
1 gallon is equal to 4 quarts
Convert to Six Packs
1 gallon is equal to 1.777778 six packs

Unit of Measurement Conversion Made Easy!

There are thousands of units of measure in use across the globe, and converting from one to another can be very difficult since each conversion requires a different formula to derive the result. Our unit of measurement conversion tools are meant to be dead easy. We break the mold of the typical dry and complicated experience. In addition to converting from one measurement to another, we provide the formula so you can see how the conversion is done, use it on you’re own calculator if you need to!

Convert units of length, weight, volume, and area between imperial and metric measures

Understanding the Metric System

The metric system makes it relatively easy to convert from one metric unit to another metric unit. The metric system uses a base unit, think meters or grams, and a prefix such as kilo or milli. The prefixes differ from the base units by differing powers of 10. So to convert within the metric system it’s usually a matter of multiplying or dividing by one of the powers of 10.

Here is a list of some of the common metric prefixes:

  • “kilo” – 1,000x larger
  • “hecto” – 100x larger
  • “deca” – 10x larger
  • “deci” – 10x smaller
  • “centi” – 100x smaller
  • “milli” – 1,000x smaller

There is a helpful mnemonic for remembering the prefixes: “King Henry Died Until Drinking Chocolate Milk.”
The u in Until refers to the base unit.