The UK gallon (imperial gallon) equals exactly 4.54609 liters, about 20% larger than the US gallon, and remains the standard fuel measurement in the United Kingdom and some Commonwealth nations. British fuel efficiency is expressed in miles per imperial gallon, which yields higher numbers than the US equivalent. One UK gallon equals approximately 1.201 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.