An Individual Taxpayer Identification Number (ITIN) is a nine-digit number issued by the IRS. It is used by individuals who are ineligible for a Social Security number (SSN) but need a taxpayer identification number for U.S. federal tax purposes.
Not having an SSN does not automatically mean you need an ITIN.
1. When Might an ITIN Be Needed?
If you are ineligible for an SSN, an ITIN may be needed to:
- File a U.S. individual income tax return
- Claim a refund of income tax withheld
- File a joint return with your spouse when eligible
- Provide a taxpayer identification number for certain treaty benefits
Spouses and dependents must have a qualifying tax purpose. Accompanying a family member to the United States does not, by itself, require an ITIN.
Reference: IRS — Instructions for Form W-7
2. How Does It Differ from an SSN?
An ITIN serves federal tax purposes. It does not authorize employment, provide immigration status, or establish eligibility for Social Security benefits.
If you qualify for an SSN, generally use that number. If an SSN is issued after you receive an ITIN, use the SSN going forward and arrange for the IRS to combine your records.
Reference: IRS — Individual Taxpayer Identification Number
3. How Do You Apply?
Generally, submit Form W-7 with the related federal income tax return and documents establishing identity and foreign status. Certain exceptions permit an application without an attached return.
Supporting documents generally must be originals or copies certified by the issuing agency. Mail and designated in-person application options are available.
Reference: IRS — How to Apply for an ITIN
4. Can an ITIN Expire?
Yes. An ITIN not used on a federal income tax return for three consecutive years generally expires on December 31 of the third year.
Review renewal requirements before using an expired ITIN on a return.
Reference: IRS — Instructions for Form W-7
Information to Gather
Review SSN eligibility, any previously issued SSN or ITIN, your filing approach, and the reason a number is needed.
We review identification-number requirements in connection with your tax filings and explain the necessary procedures. Please exclude identification numbers and passport copies from your initial inquiry.
This answer provides general information. Application eligibility and documentation requirements depend on individual circumstances.
Information reviewed: October 14, 2026
