Cups to OZ Converter

How to convert cups to fluid ounces

1 cup = 8 fluid ounces. To convert cups to fluid ounces, multiply by 8. A US customary cup is 8 US fluid ounces, about 236.6 ml (nutrition labels use a rounded 240 ml). A US fluid ounce is 1/128 of a US gallon, exactly 29.5735295625 ml.

Worked examples

• 0.75 cups = 6 fl oz (0.75 × 8)
• 2 cups = 16 fl oz (2 × 8)
• 4 cups = 32 fl oz (4 × 8)

Where this conversion comes up

Cups are used for US recipes and nutrition labels; fluid ounces for drink cans, baby bottles, cosmetics and US recipes. For liquids, 1 US cup is 8 fluid ounces. For dry ingredients by weight the answer depends on the ingredient: a cup of water weighs 8.3 oz, a cup of flour about 4.25 oz.

Quick estimate

Multiply by 8.

Common mistakes

• Dividing instead of multiplying. A fluid ounce is smaller than a cup, so the number of fluid ounces must come out larger: 0.75 cups = 6 fl oz.
• Mixing fluid ounces with weight ounces. A fluid ounce is a volume (29.57 ml); an ounce on a kitchen scale is a weight (28.35 g). A cup of flour is 8 fl oz by volume but only about 4.25 oz by weight.
• Using the imperial (UK) unit. This page uses US measures. An imperial gallon is 4.546 L (20% more than a US gallon), an imperial pint 568 ml and an imperial fluid ounce 28.41 ml.

Going the other way? Use the oz to cups converter. Related volume converters: ml to oz, oz to ml, liters to gallons, gallons to liters, liters to quarts, quarts to liters.