ITIN and SSN are both 9-digit tax identification numbers, but they serve different purposes and have different eligibility requirements:
Social Security Number (SSN):• Issued by Social Security Administration
• For U.S. citizens, permanent residents, and authorized workers
• Provides eligibility for Social Security benefits
• Can be used for employment (I-9 verification)
• Required for most government benefits
• Lifetime number (doesn't expire)
ITIN (Individual Taxpayer Identification Number):• Issued by Internal Revenue Service
• For people who can't get an SSN
• Only for federal tax purposes
• Does NOT authorize work
• Does NOT provide Social Security benefits
• Must be renewed (expires if unused for 3 years)
Key Differences:| Feature | SSN | ITIN |
|---------|-----|------|
| Issued by | SSA | IRS |
| Work authorization | Yes | No |
| SS benefits | Yes | No |
| Tax filing | Yes | Yes |
| Expires | No | Yes |
| Employment (I-9) | Yes | No |
Important Notes:• Never use ITIN on Form I-9 (employment)
• If you get SSN later, stop using ITIN
• Notify IRS when you get SSN to link records
• You can only have one or the other active
When ITIN Converts to SSN:If your status changes and you qualify for SSN:
- Apply for SSN through Social Security
- Continue using ITIN until SSN arrives
- Send letter to IRS to link ITIN history to SSN
- Stop using ITIN on new documents
We help clients understand which number they need and assist with both ITIN applications and the transition to SSN when applicable.