Below are the valid ranges for a Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or Adoption Taxpayer Identification Number (ATIN):
Social Security/Taxpayer Identification Numbers are broken down as follows:
| Area | - | Group | - | Serial |
| 1 2 3 | - | 4 5 | - | 6 7 8 9 |
When the SSN "Group" contains zeros, the SSN is a test SSN and the return will be rejected. When the SSN "Serial" contains all zeros, the return will be rejected.
An ITIN is a nine-digit number assigned by the Internal Revenue Service to taxpayers who are not eligible to obtain an SSN. It is used for tax purposes only. See the IRS website General ITIN Information for additional details.
2019 Note: ITINs that have not been used on a tax return for Tax Year 2016, Tax Year 2017, or Tax Year 2018 will expire December 31, 2019. All ITINs issued before 2013 with middle digits of 83, 84, 85, 86, or 87 (Example: (9XX-83-XXXX) will also expire on December 31, 2019.
An ATIN is issued by the Internal Revenue Service as a temporary taxpayer identification number for the child in a domestic adoption where the adopting taxpayers do not have and/or are unable to obtain the child's Social Security Number (SSN). It is to be used by the adopting taxpayers on their Federal Income Tax return to identify the child while final domestic adoption is pending.