How to convert US fluid ounces to US cups
One US fluid ounce equals 0.125 US cups, so multiply the number of US fluid ounces by 0.125:
cup = US fl oz × 0.125
US fl oz = cup ÷ 0.125 (1 cup = 8 US fl oz)
Example: 4 US fl oz → 4 × 0.125 = 0.5 cup.
Going the other way, divide by 0.125, or multiply by 8; the US cups to US fluid ounces converter does it for you.
Everyday values
| US fluid ounces | US cups | For example |
|---|---|---|
| 4 US fl oz | 0.5 cup | half a cup |
| 8 US fl oz | 1 cup | one cup |
| 12 US fl oz | 1.5 cup | a soda can |
| 16 US fl oz | 2 cup | a US pint |
| 32 US fl oz | 4 cup | a US quart |
When you need this conversion
Eight US fluid ounces make one US cup. Note that "ounces" in a dry-ingredient recipe may mean weight, not volume; 8 oz of flour by weight is nearly 2 cups.
US fluid ounce to US cup conversion table
| US fl oz | cup | US fl oz | cup |
|---|---|---|---|
| 2 US fl oz | 0.25 cup | 22 US fl oz | 2.75 cup |
| 4 US fl oz | 0.5 cup | 24 US fl oz | 3 cup |
| 6 US fl oz | 0.75 cup | 26 US fl oz | 3.25 cup |
| 8 US fl oz | 1 cup | 28 US fl oz | 3.5 cup |
| 10 US fl oz | 1.25 cup | 30 US fl oz | 3.75 cup |
| 12 US fl oz | 1.5 cup | 32 US fl oz | 4 cup |
| 14 US fl oz | 1.75 cup | 34 US fl oz | 4.25 cup |
| 16 US fl oz | 2 cup | 36 US fl oz | 4.5 cup |
| 18 US fl oz | 2.25 cup | 38 US fl oz | 4.75 cup |
| 20 US fl oz | 2.5 cup | 40 US fl oz | 5 cup |
About the units
- US fluid ounce (US fl oz): 1/128 of a US gallon, about 29.57 millilitres.
- US cup (cup): 8 US fluid ounces, about 236.6 millilitres (legal nutrition-label cup: 240 ml).
Both are units of volume. The conversion factor comes from the exact definitions above, so the calculator is exact; results are only rounded for display (up to six significant digits).
Frequently asked questions
How many US cups are in one US fluid ounce?
One US fluid ounce is 0.125 US cups. One US cup is 8 US fluid ounces.
How do I convert US fluid ounces to US cups?
Multiply the value in US fluid ounces by 0.125. To go back, divide by 0.125.
What is 4 US fl oz in US cups?
4 US fl oz = 0.5 cup.
What is 8 US fl oz in US cups?
8 US fl oz = 1 cup.
Sources
- NIST Special Publication 811 (2008), Guide for the Use of the International System of Units (SI), Appendix B: conversion factors.
- NIST Handbook 44 (2024), Appendix C: General tables of units of measurement.
Last reviewed 5 October 2026. Results are estimates; see our disclaimer.