Main articles: United States customary units and Metrication in the United States
The country retains United States customary units, constituted largely by British imperial units such as yards, miles, and degrees Fahrenheit. Distinct units include the U.S. gallon and pint volume measurements. The United States is one of three countries, along with Burma and Liberia, that has not officially adopted the metric system. However, metric units are increasingly used in science, medicine, and many industrial fields.