The liter (L) is the most widely used metric unit of volume, equal to 1,000 cubic centimeters or one cubic decimeter, serving as the standard for beverages, fuel, and household liquids worldwide. Gasoline prices, bottled water, and milk cartons all reference liters in most countries. One liter equals approximately 1.0567 US quarts or 0.2642 US gallons.

The US cup is a volume unit equal to 8 US fluid ounces or approximately 0.2366 liters, the standard measurement in American recipes and cookbooks. When a recipe calls for 'one cup of flour' or 'half a cup of sugar,' it refers to this specific volume, not a drinking vessel of arbitrary size. One US cup equals exactly 236.588 milliliters.