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Are Social Security numbers reused?

No, the Social Security Administration (SSA) does not reuse numbers. It does not reassign a Social Security number (SSN) when the person holding that nine-digit combination dies.

About 454 million SSNs have been used to date. The SSA says it issues about 5.5 million new ones a year but has enough unused numbers to last for “several generations into the future.” That’s in large part because of an overhaul of the numbering system put in place in 2011.

Until then, Social Security assigned numbers according to a geographic system put in place at the program’s inception in the mid-1930s:

  • The first three digits represented where a person was living when their SSN was issued (the numbers varied by state and got higher moving east to west).
  • The next two represented blocks of numbers within that geographic area.
  • The last four were a “serial number” to identify each individual within that block.

This method helped with the paper filing system in use at the time, but it limited the range of numbers that could be assigned in a given area. By the mid-2000s, the SSA was starting to run low on available numbers in some states.

That led to the switch in June 2011 to the current system in which new SSNs are randomly generated from first digit to last. Removing the geographic marker considerably expanded the pool of numbers available in each state and enhanced identity protection by making it harder for crooks to reconstruct SSNs using publicly available data like someone’s address.

In addition to randomizing number assignment, the SSA began using some number combos that previously had been excluded, such as allowing SSNs beginning with 7 or 8. You still won’t find an SSN starting with 000, 666 or any number in the 900s; with 00 in the middle; or with 0000 at the end.) With these changes, the SSA says it has more than 400 million numbers still available.

Keep in mind

  • Existing SSNs were not reissued or replaced when randomization started. If you got your number before June 25, 2011, it reflects the old system and includes a geographic prefix.
  • You can ask for a change in your number, but Social Security will only grant such a request in very limited circumstances.

Published July 15, 2022