How to convert fl oz to cup
cup = fl oz × 0.125. The scale factor is the source-unit factor divided by the destination-unit factor.
Worked example
For a liquid quantity of 2 fl oz converts to 0.25 cup.
- Start with 2 fl oz.
- Multiply 2 by 0.125.
- Report 0.25 cup, rounded to the precision of your original measurement.
Check the reverse conversion
1 cup = 8 fl oz. Use the us cup to us fluid ounce converter to calculate in the opposite direction. This has its own formula and reference table.
Definitions that matter
A US gallon is 3.785411784 L; an imperial gallon is 4.54609 L. US customary cups here are 236.5882365 mL, not 250 mL metric cups. Fluid ounces measure volume, not mass; density is needed to convert to grams.
The base unit for this category is L. One fl oz corresponds to 0.02957352956 liter; one cup corresponds to 0.2365882365 liter. These definitions explain the relationship rather than relying on a rounded display value.
Sources and precision
Definitions: NIST Guide to the SI. Calculations use double precision; the tool defaults to a readable rounded result, while tables show up to ten significant digits. Displaying more digits does not increase the accuracy of the original measurement.
Read our calculation methodology and content standards, or continue with us customary and metric definitions.