Cups to Ounces (cups to fl oz)
A US customary cup holds exactly 8 US fluid ounces (236.5882365 ml; the fluid ounce is 1/128 of the 231-cubic-inch gallon, NIST SP 811), so multiply cups by 8. Two and a half cups is 20 fl oz.
Formula
US fl oz = US cups × 8
Example: 0.5 US cups = 4 US fluid ounces.
Cups to Ounces chart
| US cups | US fluid ounces |
|---|---|
| 0.125 | 1 |
| 0.25 | 2 |
| 0.333 | 2.664 |
| 0.5 | 4 |
| 0.667 | 5.336 |
| 0.75 | 6 |
| 1 | 8 |
| 1.25 | 10 |
| 1.5 | 12 |
| 2 | 16 |
| 2.5 | 20 |
| 3 | 24 |
| 4 | 32 |
| 6 | 48 |
| 8 | 64 |
| 16 | 128 |
Good to know
Fractions of a cup: 1/8 cup = 1 fl oz = 2 tablespoons, 1/4 cup = 2 fl oz, 1/3 cup = 2.67 fl oz, 1/2 cup = 4 fl oz, 2/3 cup = 5.33 fl oz and 3/4 cup = 6 fl oz. A shot glass is about 1.5 fl oz, so 1/4 cup is a little more than one shot.
Drinks and bottles: a 16.9 fl oz water bottle is 2.1 cups, a 20 oz soda is 2.5 cups and a 64 oz jug is 8 cups. The 'eight glasses of water' rule is 64 fl oz, half a gallon.
Weight ounces are different: a cup of flour weighs about 4.25 oz, a cup of sugar about 7 oz and a cup of butter 8 oz. Use this chart for liquids measured in a jug, and a scale for dry ingredients.
Frequently asked questions
How many ounces are in 1 cup?
8 US fluid ounces.
How many ounces is 3/4 cup?
3/4 cup is 6 fl oz.
How many ounces is 1/3 cup?
1/3 cup is 2.67 fl oz (2 fl oz + 4 teaspoons).
How many ounces are in 4 cups?
4 cups is 32 fl oz, which is 1 quart.