Cups to Millilitres Converter
Convert cups to millilitres and select the cup volume your recipe uses. This prevents a US customary cup and a recipe-defined 250 mL cup from being silently treated as the same size.
Enter a zero or positive amount. Decimal values are supported. Only the displayed result is rounded.
The US cup factor follows the US customary relationship of 8 US fluid ounces per cup; NIST lists approximately 236.588 mL. The 250 mL option is a user-selected recipe volume, not a claim that all metric recipes use that cup size. See NIST volume conversion factors.
Formula
mL = cups × mL per selected cup
Example: 1 US customary cup is about 236.588 mL; a recipe-defined 250 mL cup is 250 mL.
About these units
The US customary cup is 8 US fluid ounces (about 236.588 mL). Some recipes specify a 250 mL cup. Check the recipe’s convention and choose it explicitly.
Everyday conversion examples
Cup sizes vary by recipe convention. Compare both options below, and select the size that the recipe actually defines before using the calculator.
| Cups | US customary cup (mL) | Recipe-defined 250 mL cup (mL) |
|---|---|---|
| 0.5 | 118.294 | 125 |
| 1 | 236.588 | 250 |
| 1.5 | 354.882 | 375 |
| 2 | 473.176 | 500 |
Examples are rounded for readability. Use the calculator above for another amount; it keeps the conversion factor until the final display.
Which cup should I choose for a US recipe?
A US customary cup is about 236.588 mL. If a recipe or measuring set explicitly defines a 250 mL cup, choose that option instead.
Does every metric recipe use a 250 mL cup?
No. The 250 mL option is only for a recipe that specifies that size. When precision matters, follow the recipe’s stated measurement convention.
Source
Conversion factors are based on customary and metric volume relationships documented by the National Institute of Standards and Technology (NIST), Guide to the SI, Appendix B.9. NIST reports rounded factors; this page displays a rounded result.