How Many Ounces in a Cup? There is a simple formula for you to calculate the ounces in a given container. Measure the width and length of the cup. Multiply them both, then divide the result by 2.
The answer is the number of ounces.
For example, if the cup is 10 inches wide and 4 inches long, the calculation is 10*4=40. 40/2=20 oz. So you see, the answer is 20 ounces.
There are 16 ounces in a cup. However, be careful. The difference between 16-ounce and 8-ounce glasses is smaller than you would think. 16 ounce glasses are only slightly larger than eight-ounce glasses. When you first start drinking, a 16-ounce glass will appear larger than a 12-ounce glass. But as you get used to it, the glass seems smaller.
A US cup is 8 US fluid ounces and a US fluid ounce is 29.5735 milliliters. But in cooking and baking there are two common types of cup measures – the US cup, which is a volume measure, and the imperial cup, which is a weight measure. A US cup volume measure is equal to 240 mL and a US imperial cup weight measure is equal to 250 g. So that means a cup is equal to 240 mL in cooking and baking.