To convert fluid ounces to cups (fl oz to cup), multiply by 0.125. 1 fluid ounce equals 0.125 cup, about 5.9 times as much as a teaspoon.
| fluid ounces | cups |
|---|---|
| 1 fluid ounce | 0.125 cup |
| 2 fluid ounces | 0.25 cup |
| 5 fluid ounces | 0.625 cup |
| 10 fluid ounces | 1.25 cup |
| 25 fluid ounces | 3.125 cup |
| 50 fluid ounces | 6.25 cup |
| 100 fluid ounces | 12.5 cup |
| 250 fluid ounces | 31.25 cup |
| 500 fluid ounces | 62.5 cup |
| 1000 fluid ounces | 125 cup |
The factor is exactly 0.125. It is a terminating decimal, so nothing on this page is rounded.
For mental arithmetic the factor is close enough to 0.125 to use directly: multiply fluid ounces by 0.125 and the answer is right to within a rounding error.
Going the other way, one cup is 8 fl oz, which is usually the easier direction to work in. Because the forward factor is small, watch the decimal place rather than the digits: a factor-of-ten slip is the common error, not a rounding one.
To anchor the scale: 10 fluid ounces is about 1.25 cup.