What is the number of cups in one gallon?

One gallon is equivalent to 16 cups. This measurement is based on the conversions between fluid volumes used in the United States. Specifically, there are 4 quarts in a gallon, and each quart contains 4 cups. Therefore, when you multiply the number of quarts (4) by the number of cups per quart (4), you arrive at the total: 4 quarts × 4 cups per quart = 16 cups in a gallon. This fundamental knowledge is essential for pharmacy practice, as accurate conversions between units are crucial in medication preparation and dosing.