Cooking

Cups to Fluid Ounces

Convert cup to fl oz quickly with this free online calculator. The page explains the conversion rule, gives practical examples and provides a quick reference table.

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CONVERTED RESULT
Decimal places
CONVERSION RULE

1 cup equals approximately 8 fl oz.

How to use the Cups to Fluid Ounces

  1. Enter the number you want to convert.
  2. Confirm the source unit shown beside the input.
  3. Choose decimal precision if you need more or less detail.
  4. Read the converted result.
  5. Copy the result when you need to use it elsewhere.

How the conversion works

1 cup equals approximately 8 fl oz.

For a simple fixed-factor conversion, the calculator multiplies the entered value by the stated factor. Temperature scales and certain specialized tools use their specific mathematical relationship instead.

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Common cup to fl oz conversions

cupfl oz
1 cup8 fl oz
2 cup16 fl oz
5 cup40 fl oz
10 cup80 fl oz
20 cup160 fl oz
50 cup400 fl oz

Example

For example, entering 1 cup gives approximately 8 fl oz using the rule above. Change the input to test your own value.

Frequently asked questions

The Cups to Fluid Ounces converts a value from cup to fl oz using the conversion relationship described on this page.
Enter your value, review the source and destination units, choose the decimal precision and read or copy the result.
1 cup equals approximately 8 fl oz.
Use enough precision for your purpose. Everyday estimates usually need fewer decimal places; technical work may require more.
It can be a useful reference calculation, but safety-critical, regulated, contractual or specialized work should be verified against the applicable authoritative standard.

Accuracy note: This calculator is a practical reference. For regulated, safety-critical or specialized work, verify the result against the applicable standard.

Page reviewed: August 24, 2026.