How Many Ounces in a Cup?
1 US customary cup = 8 US fluid ounces.
Cups to fluid ounces, without mixing up weight
US fluid ounces = US customary cups × 8. US customary cups = US fluid ounces ÷ 8. These are volume units, not ounces of weight.
A US customary cup holds exactly 8 US customary fluid ounces. For example, 1½ cups holds 12 fl oz, while 4 fl oz is ½ cup. You can type 1 1/2 or use the fraction shortcuts instead of converting the fraction to a decimal yourself.
Fluid ounces (fl oz) measure volume. Ordinary ounces (oz) measure mass. A cup of flour and a cup of water occupy the same volume but generally have different weights. There is no single cups-to-weight-ounces factor for all dry ingredients. This tool deliberately does not estimate ingredient density.
The cup standard matters. A US customary cup is 236.5882365 mL. FDA nutrition labels define a cup as 240 mL and a label fluid ounce as 30 mL. Those two labeling measures also have an eight-to-one ratio, but they must not be mixed with customary US fluid ounces.
A 250 mL metric cup is about 8.453506 US fl oz. A 284.130625 mL imperial cup is about 9.607599 US fl oz, or 10 imperial fl oz. This calculator stays on the US customary standard throughout; it does not silently change cup definitions by ingredient or location.
US customary cups to US fluid ounces (fl oz) chart
Values use the same exact factor as the calculator and are displayed to six decimal places where needed.
| US customary cups | US fluid ounces (fl oz) |
|---|---|
| 1/8 | 1 |
| 1/4 | 2 |
| 1/3 | 2.666667 |
| 1/2 | 4 |
| 2/3 | 5.333333 |
| 3/4 | 6 |
| 1 | 8 |
| 1 1/2 | 12 |
| 2 | 16 |
| 3 | 24 |
| 4 | 32 |
| 8 | 64 |
Input and rounding
Use a decimal point, a fraction such as 1/2, or a mixed number such as 1 1/2. Properly grouped thousands commas are accepted. Negative measurements, unrecognized units and incomplete numbers need to be corrected before copying. Clearing the input also clears the previous answer.
Decimal places controls display rounding, not the accuracy of your original measurement. Swap uses the underlying result rather than the rounded text. Inputs and outputs must be finite, nonnegative and no larger than one trillion. Very small positive values use scientific notation instead of being displayed as zero.
Frequently asked questions
Is a cup 8 or 16 ounces?
One US customary cup is 8 US fluid ounces. Two cups are 16 US fluid ounces, which is one US liquid pint. This does not mean every cup of an ingredient weighs 8 ounces.
How many cups are 12 fl oz?
12 US fluid ounces ÷ 8 = 1.5 US customary cups, or 1½ cups. Paste 12 fl oz for the reverse conversion.
Can I convert flour cups to ounces?
This tool converts the volume of flour to fluid ounces, not its weight. To get weight ounces, use a scale or an ingredient-specific weight source that accounts for how the ingredient was measured.
Can I enter fractions?
Yes. Enter 1/2, 1/3 or a mixed number such as 1 1/2. Use the fraction shortcuts on mobile, or the text keyboard for slash and space. A zero denominator is not valid.