Convert Milliliters to Cups – Volume Converter
This converter turns a single numeric volume in milliliters into cups using a fixed unit relationship. The default "cup" in this tool is the US customary cup commonly used in recipes and laboratory conversions.
Different contexts use different cup definitions (for example: US customary, US legal/nutrition, metric, and Imperial). The page content below explains which cup definition is used here, when to choose an alternative, and how measurement uncertainty and instrument calibration affect practical accuracy.
Interactive Converter
Convert between milliliter and us cup with precision rounding.
Quick reference table
| Milliliter | US Cup |
|---|---|
| 1 mL | 0.0042 cup |
| 5 mL | 0.0211 cup |
| 10 mL | 0.0423 cup |
| 25 mL | 0.1057 cup |
| 50 mL | 0.2113 cup |
| 100 mL | 0.4227 cup |
Methodology
The conversion is performed by dividing the input in milliliters by the canonical milliliters-per-cup constant used by this tool. For the default cup definition this tool uses 1 US customary cup = 236.5882365 milliliters. The calculation is deterministic and follows international unit conventions for converting linear multiples of volume units.
We include accuracy and compliance guidance because real-world measurement depends on instrument calibration, temperature (fluid expansion), and rounding conventions. For formal or regulated uses consult the referenced standards and local regulatory definitions before applying converted values in legal, medical, or manufacturing contexts.
Worked examples
Convert 500 mL to cups (US customary): 500 ÷ 236.5882365 = 2.11338 cups → typically displayed as 2.11 cups for cooking.
Convert 250 mL to cups using metric cup (250 mL per cup): 250 ÷ 250 = 1.00 metric cup. Using US customary cup the same 250 mL = 1.057 cups.
Nutrition label context: if a food label uses a 240 mL cup definition, 480 mL = 2.00 nutrition-cups (480 ÷ 240).
Expert Q&A
Which 'cup' definition does this converter use by default?
By default this converter uses the US customary cup defined as 236.5882365 milliliters. See the methodology and examples for alternative cup definitions and when to use them.
Why are there different cup sizes and which should I use?
Different cup sizes are historical and contextual: recipe/cooking traditions, legal/nutrition labeling, and regional standards use different values. Use the metric cup (250 mL) for most scientific and metric-based recipes, US customary (236.5882365 mL) for many North American cooking conversions, and check food labeling rules if you need legal/nutrition values (commonly 240 mL).
How accurate is the conversion?
The mathematical conversion between milliliters and cups is exact given the chosen constant. Practical accuracy depends on input precision, measuring device tolerance, fluid temperature, and rounding. For regulatory or lab measurements follow calibration and uncertainty requirements in standards such as NIST and ISO referenced below.
Can the tool account for instrument calibration or temperature?
No. This converter applies only the mathematical unit conversion. Instrument calibration, fluid thermal expansion, and measurement uncertainty must be handled separately according to laboratory procedures and standards (see citations).
I need a different cup definition. How do I convert?
Use the reference milliliters-per-cup values provided in the how_is_calculated section. To convert using a different cup, divide the milliliters by that cup's milliliters value (for example divide by 250 for a metric cup).
Sources & citations
- NIST — Guide for the Use of the International System of Units (SI) — https://www.nist.gov/publications/guide-use-international-system-units-si
- ISO 80000-1 Quantities and units (overview page) — https://www.iso.org/standard/68989.html
- U.S. Food and Drug Administration — Food labeling and nutrition (general info) — https://www.fda.gov/food
- U.S. National Agricultural Library — Food measurement and composition references — https://www.nal.usda.gov/fnic
- Occupational Safety and Health Administration (OSHA) — Safety and calibration guidance (agency homepage) — https://www.osha.gov
- IEEE Standards Association — standards and best practices (homepage) — https://standards.ieee.org