What is a Social Security number?

A Social Security number is a unique nine-digit number issued by the Social Security Administration to U.S. citizens, permanent residents, and temporary residents. It is used to track individuals for Social Security benefits, employment, and tax purposes.

A Social Security number (SSN) is a nine-digit number issued by the United States Social Security Administration that is used to track individuals for the purposes of tax collection, social security, and other government programs.