Ounces to Gallons Conversion Calculator

By

Joe Sexton

Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.

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Sexton, J. (n.d.). Ounces to Gallons Conversion Calculator. Inch Calculator. Retrieved December 9, 2025, from https://www.inchcalculator.com/convert/ounce-to-gallon/

How to Convert Ounces to Gallons

Since ounces are a unit of mass and gallons are a unit of volume, 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 ounces and gallons of an ingredient or substance, we must either multiply or divide by its density, depending on which direction we are performing the conversion.

Ounces to Gallons Formula

To convert a measurement in ounces to gallons, divide the weight 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:

gallons = ounces / 133.5265 × density

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

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

When to Convert Ounces to Gallons

Ounces and gallons 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 weight to volume 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.

Ounce to Gallon Conversion Table

More Ounce & Gallon Conversions