Free · Volume conversions

US Cups to Fluid Ounces Conversion Calculator

Convert us cups to fluid ounces with exact unit factors, editable results and an explained example.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

1 US cup = 8 US fl oz. This uses the US customary cup of eight US fluid ounces. A US legal nutrition cup, a metric cup and an imperial cup are different measures. Enter a known value in the units shown; editing a result solves the conversion in reverse.

1 US cup = 8 US fl oz

Worked example

Enter these known values and leave the other values blank.

Volume in cups
1 cups
Volume in ounces
8 US fl oz

Assumptions and limitations

  • This uses the US customary cup of eight US fluid ounces. A US legal nutrition cup, a metric cup and an imperial cup are different measures.
  • The worked example uses the starting units. A unit selection preserves the quantity, so check the unit before entering a new number.
  • Where offered, a metric cup is 250 mL, a US legal cup is 240 mL, and the metric spoon choices are 5 mL and 15 mL. Fluid ounces measure volume rather than mass.

Common questions

Which volume convention does this conversion use?

This uses the US customary cup of eight US fluid ounces. A US legal nutrition cup, a metric cup and an imperial cup are different measures.

How should I use a rounded result?

Keep enough digits for the accuracy of the original measurement. Display rounding changes the visible precision, while the calculation retains additional digits.

References

The US customary cup uses one sixteenth of the exact US liquid gallon, replacing the rounded captured cup volume. The US fluid ounce uses one 128th of the exact US liquid gallon, replacing the rounded captured reciprocal factor. Bookify replaces the captured rounded US gallon with the exact 3.785411784-liter definition.

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