Cups to Ounces Converter

How to use the cups to ounces converter

1. Enter a number of cups to convert to fluid ounces, or enter fluid ounces to convert to cups.
2. The result updates automatically as you type.
3. Leave one field empty; if both are filled, the cups value takes priority.

How the conversion works

In the US customary system, one cup equals exactly 8 US fluid ounces. To convert cups to ounces, multiply by 8. To convert fluid ounces to cups, divide by 8.

For example, 2.5 cups multiplied by 8 gives 20 fluid ounces. Conversely, 12 fluid ounces divided by 8 gives 1.5 cups. This cups to ounces relationship holds for any liquid measured in US customary units. Because the factor is an exact integer, there is no rounding error when converting whole numbers in either direction.

Common cooking conversions

Recipes frequently use fractions of a cup. Here is a reference table of common amounts converted to fluid ounces:

Memorizing these common fractions saves time when you are working quickly in the kitchen without a calculator nearby.

US cups versus other systems

The US customary cup is defined as exactly 236.5882365 milliliters, which makes it equal to 8 US fluid ounces. However, not every country uses the same cup size. The metric cup used in Australia, Canada and New Zealand is 250 mL. The older UK imperial cup is 284.131 mL, or 10 imperial fluid ounces.

When following a recipe from another country, check which cup standard it assumes. If you need to work with metric volumes instead, a tool like ml to ounces can help bridge the gap between metric milliliters and US fluid ounces.

Fluid ounces versus weight ounces

A frequent mistake in the kitchen is confusing fluid ounces with ounces of weight. Fluid ounces measure volume, while weight ounces measure mass. One cup of water weighs about 8.3 weight ounces, not exactly 8, because the density of water is slightly more than 1 gram per milliliter at room temperature.

For dry ingredients like flour or sugar, the weight of one cup varies dramatically depending on how densely the ingredient is packed. Always use fluid ounces when measuring liquids by volume and weight ounces when measuring by mass. This cups to ounces converter handles only fluid ounces for volume measurement, so do not use it to figure out how much a cup of flour weighs on a scale.

Scaling recipes up or down

When doubling a recipe that calls for 3/4 cup of broth, you need 1.5 cups, which is 12 fluid ounces. Halving a recipe that requires 10 fluid ounces means you need 1.25 cups. Converting between cups and fluid ounces makes these calculations straightforward without needing to work with awkward fractions.

If your recipe uses larger units, you might also find it helpful to convert through pints to cups first, since one US pint equals two cups or 16 fluid ounces. Working step by step through pints, then cups, then fluid ounces keeps the math simple even for large batches.

Worked examples

Each result below was produced by the same code the tool runs, so you can check your own numbers against them.

Reference pages

• Cooking conversions: cups to grams: baking ingredients with a chart and calculator.