Ounces to Cups Converter (oz to cups)

How to Convert Ounces to Cups

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.

Full bio

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

Dry vs. Liquid Ounces

When converting ounces to cups, it's important to keep in mind that dry measurements, such as flour or sugar, are measured by weight, and liquid measurements, such as water, are measured by volume.

When measuring a liquid, the measurement is actually the volume of liquid in fluid ounces, while for dry measurements, it's a weight. This is important to remember since there are different conversion formulas for each.

You'll also need a different type of measuring cup, depending on whether the ingredient is dry or liquid. Dry measuring cups are typically made of plastic or metal and are shaped more like a scoop, while liquid measuring cups are usually transparent glass, plastic, or silicone with measurement lines along the outside.

How to Convert Dry Ounces to Cups

To convert a measurement in ounces to cups, divide the weight by 8.3454 times the density of the ingredient or material.

You can use this simple formula to convert:

Thus, the volume in cups is equal to the weight in ounces divided by 8.3454 times the density of the ingredient or material.

How to Convert Fluid Ounces to Cups

The conversion for fluid ounces is more straightforward since both units are volumes.

To convert fluid ounces to cups, divide the volume by the conversion ratio.

Since one cup is equal to 8 fluid ounces, you can use this simple formula to convert:

The volume in cups is equal to the fluid ounces divided by 8.

When to Convert Ounces to Cups

Ounces and cups 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.

For cooking and baking ingredients, you can get more specific results using our butter, flour, and sugar conversion calculators.

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]

Keep reading to learn more about each unit of measure.