How many fluid ounces are there in a cup?

8.12.

Using United States customary measures, 1 cup is equal to 8.12 liquid ounces. There is no single standard measure for a cup, however.  In the United Kingdom, 1 imperial cup (equivalent to 1.2 US customary cups) has 10 imperial fluid ounces, and in Australia, Canada and New Zealand 1 metric cup has 8.8 UK imperial liquid ounces or 8.45 US customary fluid ounces.