What number do Social Security numbers not start with?

In an effort to reduce identity theft and increase the quantity of SSNs available the issuing methodology was changed in 2011, some numbers were left out…

What number do Social Security numbers not start with?
Kevin Dietsch AFP

Prior to the 2011 methodology change for how the Social Security Administration issued nine-digit Social Security Numbers, the agency used a system to aid in the pre-computer-age records filing. The first three digits indicated the geographical area of an applicant’s mailing address with the remaining six divided into two groups to collate workers’ records.

However, as the nation grew, and ever greater numbers settled in once sparsely populated areas when the program was created, the Social Security Administration’s allocation of numbers for regions ran into a crunch. Killing two birds with one stone, the agency implemented a randomization numbering scheme but there were some number combinations that were avoided.

Social Security Administration randomizes SSNs

Despite rumors on the internet the numbers on Social Security cards prior to the 2011 switch were pretty mundane for clerical use. At the beginning, the first three digits represented the state in which the card was issued but not necessarily the state the cardholder was from. Starting in 1973 all cards were issued from the central office in Maryland, so the first three digits were assigned based on an applicant’s Zip Code.

By removing the Zip Code based allocation numbering system with the shift to randomization the agency was able to extend the longevity of the nine-digit Social Security Number in all areas of the country without any major changes. It also had the added benefit of providing additional protection against identity theft.

Prior to the changes the number “8” and “9” were not used for the first digit, and “7” was reserved for specific groups like railroad employees. Nor were any Social Security Numbers issued with “000” or “666” for the first three digits. Since 2011 Social Security numbers can now use “7” and “8” for the first digit regardless of region or type of employment. However, no Social Security Numbers will be issued with “9” as the first digit or starting with “000” or “666”.

Likewise, as before the switch to randomization the fourth and fifth digits will never be “00” nor “0000” in the final four positions.

Verifying Social Security Numbers

The Social Security Administration allows employers and third parties to verify employees’ and new hires’ Social Security Numbers. The Social Security Number Verification Service can be used to confirm that a business’ records match Social Security's records for the purpose of wage reporting (Form W-2).

The agency’s online tool offers two verification methods. One will give a user results immediately but only allows the verification of 10 names at a time. A second option allows a company to upload files of up to 250,000 names and Social Security Numbers overnight. The results should be accessible by the next government business day.