Select the conversion direction, enter the known volume and unit, then select Calculate. Options include US customary cups, 250 mL metric cups, milliliters, liters, US fl oz, and imperial fl oz; zero volume is valid and negative volume is not.
Assumptions Assumptions
- Conversions are volume-to-volume only—no density or weight adjustments.
- Measurements are level (not heaping or packed) and taken at typical room temperature.
- Unit standards used: US cup = 236.5882365 mL; Metric cup = 250 mL; US fl oz = 29.5735295625 mL; Imperial fl oz = 28.4130625 mL.
- Imperial cup sizes are not supported; choose US or metric cups. Imperial fl oz is supported as a separate option.
When to Use This Calculator
- Scaling recipes up or down when ingredient units differ (cups vs. fl oz).
- Standardizing recipe cards across US and metric kitchens.
- Quick kitchen math without looking up separate conversion charts.
Input Definitions
- Cups — select US (236.5882365 mL) or Metric (250 mL), or enter directly in mL/L.
- Fluid Ounces — select US (29.5735295625 mL) or Imperial (28.4130625 mL).
- Conversions — US: fl oz = cups × 8; cups = fl oz ÷ 8. General: fl oz = cups × (cup_mL ÷ fl_oz_mL).
Cups to fl oz Formula
The following formulas convert cups to fluid ounces and back. US customary units are shown first, followed by a general formula using milliliters.
- US cup = 236.5882365 mL
- Metric cup = 250 mL.
- US fluid ounce = 29.5735295625 mL
- Imperial fluid ounce = 28.4130625 mL.
How do you convert cups to fluid ounces? In US cooking, multiply cups by 8 to get fluid ounces. For other standards, first convert the cup size to mL, then divide by the chosen fl oz size in mL.
How do you convert fluid ounces to cups? For US units, divide fluid ounces by 8. For other standards, multiply fl oz by its mL size and divide by the chosen cup size in mL.
Cups to fl oz Conversion Table
| Cups (US) | Fluid Ounces (US) |
|---|---|
| 1/16 | 0.500 |
| ⅛ | 1.000 |
| 1/6 | 1.333 |
| ¼ | 2.000 |
| ⅓ | 2.667 |
| ⅜ | 3.000 |
| ½ | 4.000 |
| ⅝ | 5.000 |
| ⅔ | 5.333 |
| ¾ | 6.000 |
| ⅞ | 7.000 |
| 1 | 8.000 |
| 1¼ | 10.000 |
| 1⅓ | 10.667 |
| 1½ | 12.000 |
| 1¾ | 14.000 |
| 2 | 16.000 |
| 2½ | 20.000 |
| 3 | 24.000 |
| 4 | 32.000 |
| * US customary: 1 cup = 8 fluid ounces. | |
Example Problem
Convert 2.5 US cups to US fluid ounces.
Use the US formula: fl oz = cups × 8.
fl oz = 2.5 × 8 = 20 fl oz
