How to Convert US cups to US fluid ounces (cup to fl oz)
Volume conversions help with baking from American recipes, comparing petrol prices quoted per gallon abroad with pump prices per litre here, and reading PUB water bills in cubic metres. This guide shows how to convert us cups into us fluid ounces by hand, with examples and a quick-reference table.
The conversion
To convert us cups to us fluid ounces, multiply the value by 8. To go the other way, divide by the same number (or multiply by 0.125). For a quick estimate, multiply by about 8.
US fluid ounces = us cups × 8
Worked examples
- 3 cup = 24 fl oz
- 12.5 cup = 100 fl oz
- 75 cup = 600 fl oz
US cups to US fluid ounces table
| US cups | US fluid ounces |
|---|---|
| 1 cup | 8 fl oz |
| 2 cup | 16 fl oz |
| 5 cup | 40 fl oz |
| 10 cup | 80 fl oz |
| 20 cup | 160 fl oz |
| 25 cup | 200 fl oz |
| 50 cup | 400 fl oz |
| 100 cup | 800 fl oz |
| 250 cup | 2,000 fl oz |
| 500 cup | 4,000 fl oz |
| 1,000 cup | 8,000 fl oz |
Common questions
Is cup to fl oz exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the US fluid ounces to US cups converter.
Mistakes to avoid
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Background
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For any value, use the US cups to US fluid ounces Converter or browse all volume converters.
Run your own numbers: US cups to US fluid ounces Converter