Convert US Cup to Milliliter

The US customary cup converts to exactly 236.5882365 mL — a figure derived from the US gallon (3.785411784 L), divided by 16, since there are 16 cups per gallon. When scaling a recipe up or down, multiplying the cup count by 236.588 gives a precise milliliter figure that any kitchen scale or laboratory cylinder can accommodate.

Recipe adaptation between American and metric cookbooks is the primary use case. A pound-cake recipe calling for 2 cups of butter (473.2 mL) and 3 cups of sugar (709.8 mL) can be converted to milliliter weights for a digital scale — though for dry goods, weight in grams is more reliable than volume in any unit. For liquids, mL is precise and cups are convenient; knowing the conversion lets you use either.

The distinction between the customary cup (236.588 mL) and the nutrition-labeling cup (240 mL) cuts both ways here. A recipe that calls for '1 cup' means the 236.588 mL measure. A smoothie app that tracks your intake in cups may use the 240 mL definition for consistency with nutrition labels. Neither is wrong, but mixing the two definitions in the same recipe or calculation introduces a small but real error. When precision matters — brewing, pharmaceuticals, chemistry demonstrations — always state which cup definition you are using.