The milliliter (mL) is a metric unit of volume equal to one-thousandth of a liter, widely used in medicine, cooking, and chemistry for measuring small liquid quantities. Cough syrup dosages, perfume bottles, and laboratory reagents are all commonly labeled in milliliters. One milliliter equals exactly one cubic centimeter, making it interchangeable with cm³ in scientific contexts.

The US gallon (gal) is an imperial volume unit equal to exactly 3.7854 liters, the standard measurement for fuel, milk, and paint in the United States. Gasoline prices at American pumps are always quoted per gallon, and US vehicle fuel efficiency is measured in miles per gallon. One US gallon equals 4 US quarts or 8 US pints.