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 fluid ounce (fl oz) is a volume unit equal to approximately 29.574 milliliters, used to label beverages, cosmetics, and personal care products in the United States. Beverage cans, shampoo bottles, and skincare serums all display their contents in fluid ounces for American consumers. One fluid ounce equals exactly 1/128 of a US gallon or roughly 2 tablespoons.