The conversion factor
1 cup equals 240.0 milliliters. Multiply your cups value by 240.0 to get milliliters; divide to go back. For the reverse direction, use the milliliters to cups converter or the full volume converter.
Where this conversion comes up
Mixing metric and imperial is a daily reality in travel, shipping, recipes, fitness apps, and spec sheets — this page gives the exact factor plus a scannable table for the values people actually need.