OZ to Cups Converter

How to convert fluid ounces to cups

1 fluid ounce = 0.125 cups. To convert fluid ounces to cups, divide by 8 (or multiply by 0.125). A US fluid ounce is 1/128 of a US gallon, exactly 29.5735295625 ml. A US customary cup is 8 US fluid ounces, about 236.6 ml (nutrition labels use a rounded 240 ml).

Worked examples

• 4 fluid ounces = 0.5 cup (4 ÷ 8)
• 12 fluid ounces = 1.5 cup (12 ÷ 8)
• 32 fluid ounces = 4 cup (32 ÷ 8)

Where this conversion comes up

Fluid ounces are used for drink cans, baby bottles, cosmetics and US recipes; cups for US recipes and nutrition labels. Applies to liquids measured by volume: 8 fl oz is 1 cup. Dry ingredients in weight ounces (flour, sugar) do not convert this way, because a cup of flour weighs about 4.25 oz.

Quick estimate

Divide by 8.

Common mistakes

• Multiplying instead of dividing. A cup is larger than a fluid ounce, so the number of cups must come out smaller: 4 fluid ounces = 0.5 cup.
• 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.
• Rounding too early. Keep the full factor until the last step; rounding 0.125 to 0.1 first puts large values noticeably off.

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