Individual Taxpayer Identification Number: Complete 2026 Guide

What Does Individual Taxpayer Identification Number Mean in 2026?

The phrase “Individual Taxpayer Identification Number” is the IRS's formal name for the ITIN. The acronym ITIN is the common usage; both refer to the same number. The IRS introduced the program in July 1996 to give non-resident aliens, their spouses, and their dependents a legal way to file US tax returns. Before 1996, non-residents with US income had no compliant identifier.

The legal authority for the Individual Taxpayer Identification Number is 26 U.S.C. Section 6109, which directs every person filing a US tax return to include a unique identifying number. Per IRS Publication 1915, the ITIN is restricted to federal tax purposes only. It does not function as immigration documentation, work authorization, or proof of lawful presence.

For the shorter conversational explanation, see what is an ITIN. For the everyday meaning page, see ITIN number meaning.

Who Issues the Individual Taxpayer Identification Number?

The Internal Revenue Service is the sole issuing authority for the Individual Taxpayer Identification Number. Every application moves through the IRS ITIN Operation center at P.O. Box 149342, Austin, TX 78714-9342. Approximately 4.5 million active ITINs are on file with the IRS as of 2026, according to the National Taxpayer Advocate annual report.

The IRS authorizes 2 categories of intermediaries to assist applicants: Certifying Acceptance Agents (CAAs) who verify identity documents and forward the packet, and Acceptance Agents (AAs) who help complete the form but cannot verify identity. CAAs operate under IRS Publication 4520 and must hold an active agreement with the IRS Stakeholder Partnerships, Education, and Communication (SPEC) office.

What Is the Individual Taxpayer Identification Number Used For?

The Individual Taxpayer Identification Number has 6 documented federal tax uses and several non-federal financial uses. The IRS confines its purpose to tax administration, but private institutions commonly accept the number for identity-bound financial products.

• Filing a federal tax return. Form 1040 (resident aliens), 1040-NR (non-resident aliens), and Form 5472 with pro forma 1120 (foreign-owned single-member LLCs).
• Claiming tax treaty benefits. The United States maintains income tax treaties with 67+ countries. Form W-8BEN requires a US TIN to claim reduced withholding rates.
• Reporting passive US income. Dividends, interest, royalties, and rental income paid to foreign persons require an ITIN for Form 1042-S reporting.
• Receiving tax refunds. An ITIN holder filing a return with overpaid withholding is eligible for a refund via direct deposit or paper check.
• Claiming dependents on a US return. Spouses and children listed on a joint return need their own ITINs if they cannot get an SSN.
• Tax credit eligibility. ITIN holders qualify for the Child Tax Credit (for children with SSNs) and the Credit for Other Dependents under IRC Section 24.

Non-tax uses include opening US bank accounts at participating institutions, applying for ITIN-friendly credit cards, and qualifying for ITIN mortgage products. See the full list of ITIN uses.

What Is the Individual Taxpayer Identification Number Format?

Every ITIN is a 9-digit number formatted 9XX-XX-XXXX with the first digit always equal to 9. The middle two digits (positions 4 and 5) fall in 4 ranges reserved by the IRS: 50-65, 70-88, 90-92, and 94-99. These middle digits separate ITINs from SSNs, which never start with 9 and never use these middle-digit ranges.

Deeper format mechanics, including the middle-digit assignment rules and the rolling expiration cohorts, live on the ITIN format page and the ITIN example page.

How Does the Individual Taxpayer Identification Number Differ From an SSN?

Both numbers are 9-digit tax identifiers, but they originate in different agencies, serve different populations, and confer different rights. 5 differences matter most.

• Issuing agency. SSN is issued by the Social Security Administration; ITIN is issued by the IRS.
• Eligibility. SSN requires US citizenship or work-eligible immigration status; ITIN is for people ineligible for an SSN.
• Work authorization. SSN grants work authorization when paired with valid status; ITIN does not.
• Benefits. SSN unlocks Social Security retirement, disability, and survivor benefits; ITIN does not.
• Expiration. SSNs do not expire; ITINs expire after 3 consecutive years of non-use.

Full comparison and a per-row breakdown live on the ITIN vs SSN page.

How Do You Apply for an Individual Taxpayer Identification Number?

Application requires 3 components: a completed Form W-7, a federal tax return (with exceptions), and original or certified-copy identity documents. The standard channel for non-residents is a Certifying Acceptance Agent who verifies documents locally so the applicant's passport never leaves their possession.

1. Complete Form W-7. Select the correct reason code on line 6 (6a through 6h).
2. Attach the federal tax return. Most applicants submit Form 1040 or 1040-NR. Five IRS exceptions waive the attached-return requirement.
3. Gather identity proof. A current passport is the only standalone document. Without a passport, 2 documents from the IRS list of 13 acceptable IDs are required.
4. Submit through a CAA, IRS mail, or IRS TAC visit. CAA submissions retain the applicant's passport; mail submissions ship the original to Austin, TX.

The procedural deep-dive lives on the how to get an ITIN guide. Form-specific details live on the Form W-7 Instructions page.

When Does the Individual Taxpayer Identification Number Expire?

An ITIN expires on December 31 of the third consecutive tax year it is not used on a federal return. ITINs with middle digits 70 through 88 were deactivated under the IRS rolling expiration program completed in 2020. Holders of expired ITINs must renew via Form W-7 before they can file their next return.

See the ITIN expiration guide and the ITIN renewal guide for the renewal mechanics.