Gallons to Ounces Conversion Calculator

Enter the volume in gallons below to calculate the weight in ounces.


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1 gal = 133.52647123233 oz

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How to Convert Gallons to Ounces

Since gallons are a unit of volume and ounces are a unit of mass, which are different physical quantities, we need to know one more physical quantity of the ingredient or substance to convert between them. In this case, we need to account for the density of the substance whenever we do a conversion.

Therefore, to convert between gallons and ounces of an ingredient or substance, we must either multiply or divide by its density, depending on which direction we are performing the conversion.

Gallons to Ounces Formula

To convert a measurement in gallons to ounces, multiply the volume by the density of the ingredient or material. Note that in order for this to work, the density must be in ounces per gallon (oz/gal).

If the density is given in grams per milliliter (g/mL), then first multiply the density by 133.5265 to convert to oz/gal.

For a density given in g/mL, you can use this simple formula to convert:

ounces = gallons × 133.5265 × density

Thus, the weight in ounces is equal to the volume in gallons multiplied by 133.5265 times the density (in g/mL) of the ingredient, substance, or material.

For example, here's how to convert 5 gallons to ounces for an ingredient with a density of 0.7 g/mL.
ounces = 5 gal × 133.5265 × 0.7 g/mL = 467.3426 oz

This formula is for converting to ounces in weight, if you're trying to convert to a volume measurement in fluid ounces, try our gallons to fluid ounces calculator.

When to Convert Gallons to Ounces

Gallons and ounces are both commonly used to measure cooking ingredients.

For cooking applications, most chefs suggest measuring dry ingredients by weight rather than volume to improve accuracy in the measurements.[1] The density of dry ingredients can vary for a variety of reasons, such as compaction and clumping.

The best way to ensure an accurate conversion is to use a scale. When a scale is not available, a calculator like the one above is a good way to estimate the volume to weight conversion.

Another useful application of weight and volume conversions is chemistry. When performing chemical reactions by combining separate chemicals to produce a new chemical, one must know the exact amount of each chemical to add in order to maximize the yield of the reaction.

It is common to mix powdered chemicals with liquid, or aqueous, chemicals, and this is where it becomes very useful to convert between weights and volumes.[2]

A third application of weight and volume conversions is when shipping freight when calculating the volumetric weight for cargo and packages. Trucks, ships, and airplanes are limited in the amount of weight or volume they can transport, so if one of those quantities is known, but the limitation is on the other, then it becomes necessary to convert between the two so as not to overload the shipping vehicle.

Keep reading to learn more about each unit of measure.

How Many Ounces Are in a Gallon?

The actual weight of a gallon will vary depending on the density of the material. The table below shows how many ounces of various wet and dry ingredients are in a gallon.

Gallon measurements converted to ounces for commonly used cooking and baking ingredients.
Volume in Gallons: Weight in Ounces of:
Water Milk Cooking Oil All Purpose Flour Granulated Sugar
1/8 gal 16.69 oz 17.19 oz 14.69 oz 8.8294 oz 14.11 oz
1/4 gal 33.38 oz 34.38 oz 29.38 oz 17.66 oz 28.22 oz
1/3 gal 44.51 oz 45.84 oz 39.17 oz 23.55 oz 37.63 oz
1/2 gal 66.76 oz 68.77 oz 58.75 oz 35.32 oz 56.44 oz
2/3 gal 89.02 oz 91.69 oz 78.34 oz 47.09 oz 75.25 oz
3/4 gal 100.14 oz 103.15 oz 88.13 oz 52.98 oz 84.66 oz
1 gal 133.53 oz 137.53 oz 117.5 oz 70.64 oz 112.88 oz

What Is a Gallon?

The US liquid gallon is a unit of fluid volume equal to four quarts, eight pints, or sixteen cups.[3] 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.

What Is an Ounce?

One ounce is a unit of mass/weight equal to 1/16 of a pound or 28.349523 grams. The common ounce should not be confused with the troy ounce, which is equal to 1/12 of a troy pound.[4]

The ounce is a US customary and imperial unit of mass. Ounces can be abbreviated as oz; for example, 1 ounce can be written as 1 oz.

An ounce is also frequently referred to as a unit of weight. While technically, an ounce is a measure of mass, and weight is actually a measure of force, the two are equivalent as long as we are performing our calculations on Earth.

For example, an object with a mass of 1 ounce weighs 1 ounce on Earth, but only weighs one-sixth of that on the moon, yet still has the same mass.

Learn more about ounces.


  1. National Institute of Standards & Technology, Culinary Measurement Tips,
  2. CK-12 Foundation, Introductory Chemistry (CK-12) - 12.6: Mass-Volume Stoichiometry,
  3. National Institute of Standards and Technology, Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, Handbook 44 - 2019 Edition,
  4. James Bucki, Troy Ounce vs. Ounce, The Spruce,

More Gallon & Ounce Conversions