How to Decipher a Social Security Number

Each Social Security number has three parts, though the first is the most informative. The first three digits can tell you what geographical area the person had a connection to and when he received his number. The last two parts can help you judge whether a Social Security number is a real, valid number. While a person is still living, the Social Security Administration keeps other information confidential, but after a person dies, you can also find out a little more.

1
Compare the first three digits to the "Chart of SSN Assignments by State" on the Social Security Administration's website. If the person received her number before 1972, the state indicates the location of the office that issued her card. After 1972, the area number reflects the mailing address that the person used when he applied for his card.
2
Check the Social Security Administration's current "High Group List" to see the highest group numbers issued for each area number. The two-digit group number follows the three-digit area number. However, group numbers don't run in normal numerical order. The Social Security Administration issues odd group numbers for each area from 01 to 09, then switches to even numbers starting with 10 and ending with 98. Then they start over with 02 and use the even numbers to 08, switching again to the odd numbers from 11 to 99.
The Social Security website shows the highest group numbers currently being issued for each area, so if someone gives you a Social Security number that's sequentially beyond that, you know it's fake. The final four digits are the serial numbers. They run in numerical order beginning with 0001. When someone in an area receives 9999, that area begins a new group number and begins again with a serial number of 0001.
3
Check the Social Security Death Index if you suspect the number belongs to someone who died after 1962. The list is incomplete for people who died before 1962, but some numbers for those people may appear on the index as well. If the person has died, you can find her name, birth date, death date and place of death in the Social Security Death Index.