Fluid Ounces to Cups Converter

About the fl oz to cup calculation

One fluid ounce is exactly 0.125 cups, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The US fluid ounce. Measures volume, not weight — quite separate from the ounce. The US legal cup is 240 ml; the customary cup used in recipes is 236.6 ml.

Formula

cup = fl oz × 0.125

1 fl oz = 0.125 cup
1 cup = 8 fl oz

Worked example

To convert 8 fl oz, multiply by 0.125: 8 × 0.125 = 1 cup.

Frequently asked questions

How many cups are in a fluid ounce?

There are 0.125 cups in one fluid ounce. To convert any amount, multiply the number of fluid ounces by 0.125.

How do I convert cups back to fluid ounces?

Divide instead of multiplying, or equivalently multiply by 8. One cup is 8 fluid ounces.

Is this conversion exact?

Yes. Since the international agreement of 1959, the relationship between fluid ounces and cups is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.

Where is each of these units used?

Fluid Ounces: the US fluid ounce. Measures volume, not weight — quite separate from the ounce. Cups: the US legal cup is 240 ml; the customary cup used in recipes is 236.6 ml.

Sources

• NIST Special Publication 811 — Guide for the Use of the International System of Units