How many fluid ounces are in a cup?
8 fl oz
A US cup is 8 fluid ounces. Fluid ounces measure volume, not weight, so they only match weight ounces for water-like liquids.
Cups to fluid ounces
| cups | fluid ounces |
|---|---|
| ¼ cup | 2 fl oz |
| ½ cup | 4 fl oz |
| 1 cup | 8 fl oz |
| 2 cup | 16 fl oz |
| 4 cup | 32 fl oz |
US customary measures.