The National Origins Formula was a law that was used in the United States to decide who could be allowed to come to the United States and become a citizen. This law was used from 1924 to 1965. It said that the number of people from each country who could come to the United States was limited, and most people from some countries were not allowed at all. This meant that some people who wanted to come to the United States could not. The law was changed in 1965 so that everyone could come to the United States, no matter where they were from.