What Is an ITIN? The IRS Tax ID Number, Explained

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 6, 2026 · Last updated Aug 6, 2026

An ITIN is a 9-digit IRS tax processing number (format 9XX-XX-XXXX) for people who must file U.S. taxes but can't get a Social Security number. The IRS issues it regardless of immigration status. An ITIN does not authorize work, provide Social Security benefits, or qualify you for the Earned Income Tax Credit - it exists only for federal tax filing and reporting.

What an ITIN Is (Plain English)

An Individual Taxpayer Identification Number (ITIN) is a 9-digit number the IRS issues to a person who needs a U.S. taxpayer identification number for federal tax purposes but is not eligible for a Social Security number (SSN). It is a tax-processing number and nothing more - it lets the IRS match a tax return, payment, or information report to a specific individual who cannot obtain an SSN from the Social Security Administration.

An ITIN always begins with the digit 9 and is formatted exactly like a Social Security number, as 9XX-XX-XXXX. Because it shares that nine-digit shape, an ITIN is easy to confuse with an SSN on paper, but the two are issued by different agencies for different purposes. The IRS issues ITINs; the Social Security Administration issues SSNs. An ITIN is also distinct from an Employer Identification Number (EIN), which identifies a business rather than a person.

Critically, the IRS issues an ITIN regardless of immigration status, because both resident and nonresident aliens can have a U.S. tax filing or reporting obligation. The number carries no immigration meaning and is used only inside the federal tax system.

Why the ITIN Exists (Legal Basis)

The ITIN exists because federal law requires an identifying number on tax returns. Under 26 U.S. Code § 6109, every person who files a return, statement, or other document must include "such identifying number as may be prescribed for securing proper identification." For individuals, the default identifying number is the Social Security number - but millions of people who owe U.S. tax or must be reported on a U.S. return cannot get an SSN.

Section 6109 gives the Secretary of the Treasury authority to prescribe an alternative identifying number for those individuals, and section 6109(i) specifically addresses ITINs for people who are not eligible for an SSN. That subsection also sets the modern expiration rule: an ITIN issued after December 31, 2012 expires if the holder does not file a return for three consecutive taxable years. The statute contemplates that applications may be submitted in person to IRS employees, through IRS-approved community-based certifying acceptance agents, or by mail.

In short, the ITIN is the mechanism Congress and the IRS built so that anyone with a U.S. tax obligation can be identified on a return - whether they are a foreign investor, a nonresident student, or the spouse or dependent of a U.S. taxpayer - even when the SSN system is closed to them.

What an ITIN Does Not Do

An ITIN is narrower than most people assume. The IRS is explicit that having an ITIN does not:

• Authorize you to work legally in the United States;
• Provide or change your immigration status;
• Qualify you for Social Security benefits;
• Qualify you for the Earned Income Tax Credit (EITC); or
• Serve as identification outside the federal tax system.

The EITC point is a common trap. To claim the Earned Income Tax Credit, the IRS requires that you, your spouse if filing jointly, and any qualifying child each have a valid Social Security number issued on or before the return's due date. An ITIN never satisfies that test. ITIN filers may still be eligible for certain other benefits, such as the Child Tax Credit rules that apply to their situation, but the EITC is off-limits. Because an ITIN is not proof of work authorization or immigration status, it should never be presented as a general-purpose ID.

How to Get an ITIN: Form W-7 and Documents

Form W-7, "Application for IRS Individual Taxpayer Identification Number," is the only way to apply for or renew an ITIN. You submit Form W-7 together with two things: the federal tax return that creates your filing need, and original documents (or certified copies) proving your identity and foreign status. On the form, you choose whether you are applying for a new ITIN or renewing an existing one, and you check the reason-for-applying box (a through h) that fits your situation - for example, a nonresident alien filing a U.S. return, a U.S. resident alien filing a return, or a dependent or spouse of a U.S. citizen or resident alien. A full step-by-step walkthrough lives on our how to get an ITIN guide.

For identity and foreign-status proof, a valid passport is the only stand-alone document the IRS accepts. Without a passport, you must provide at least two documents from the IRS list - such as a national ID card, U.S. or foreign driver's license, USCIS photo ID, visa, birth certificate, or school or medical records for dependents - and at least one must show a photograph unless the applicant is under 14.

You can submit the application three ways, according to the IRS How to apply for an ITIN page:

1. By mail - send Form W-7, your return, and original documents to the IRS ITIN Operation, P.O. Box 149342, Austin, TX 78714-9342.
2. Through a Certifying Acceptance Agent (CAA) - an IRS-authorized agent who reviews and authenticates your documents so you do not have to mail original passports and IDs to the IRS. CAAs may charge a fee.
3. At an IRS Taxpayer Assistance Center - by appointment, where staff can review Form W-7 and authenticate most documents in person at no charge.

Once submitted, the IRS says to allow about 7 weeks for a notice with your ITIN - and 9 to 11 weeks if you apply during peak tax season (January 15 to April 30) or from overseas. There is no fee to file Form W-7 itself; only optional CAA services carry a cost.

Most applicants must attach a completed federal tax return (Form 1040 or 1040-NR) to Form W-7. A limited set of exceptions in the Instructions for Form W-7 lets certain people apply without a return - for example, some who receive treaty-benefit income, scholarships or fellowships, mortgage interest, or proceeds from disposing of U.S. real property.

Who Needs an ITIN?

You need an ITIN if you have a U.S. federal tax purpose and are not eligible for a Social Security number. The IRS issues ITINs to both resident and nonresident aliens and to their spouses and dependents. Typical people who need one include:

• A nonresident alien who must file a U.S. tax return (for example, to report U.S.-source income or claim a tax-treaty benefit);
• A resident alien who must file a return based on the number of days present in the U.S. but who cannot get an SSN;
• A spouse or dependent of a U.S. citizen or resident alien who is being claimed on a return;
• A nonresident student, professor, or researcher filing a U.S. return or claiming an exception; and
• A foreign person who must be furnished a taxpayer ID for a withholding or information return.

You do not need an ITIN if you already have an SSN or are eligible to get one - in that case you use the SSN. And you do not use an ITIN to run a business: an entity applies for an EIN instead. If you are a founder without an SSN, note that you can still obtain a business EIN - see can you get an EIN without an SSN?

ITIN vs. SSN vs. EIN

All three are nine-digit U.S. tax identification numbers, but they identify different things and come from different processes. The table compares them at a glance.

The short version: use an SSN if you are eligible for one; use an ITIN if you are an individual who is not; and use an EIN for a business, estate, or trust. For a deeper individual-number comparison, see ITIN vs. SSN. To get a business number, see how to get an EIN. Note that the responsible party for a business EIN application can use an ITIN in place of an SSN.

ITIN Expiration and Renewal

An ITIN is not permanent. Under the IRS renewal rules, if an ITIN is not used on a U.S. federal tax return for any three consecutive tax years, it expires on December 31 after that third year of non-use. This mirrors the statutory rule in 26 U.S.C. § 6109(i) for ITINs issued after 2012.

You only need to renew an expired ITIN if it will appear on a federal tax return you are filing. Expired ITINs can still be used on information returns such as Form 1099, so an expiration alone does not always require action. When you do need to renew, you file Form W-7 again, check "Renew an existing ITIN" in the application-type section, select your reason category, and enter the ITIN and the name under which it was issued.

Filing a return with an expired ITIN can cause processing delays, reduced or delayed refunds, and the loss of certain credits or exemptions until the number is renewed, so it is worth renewing before the filing season if you know you will file.

Examples: Common ITIN Situations

These short scenarios show when an ITIN is the right number:

• Foreign investor. A resident of another country earns rental income from a U.S. property and must file Form 1040-NR. With no SSN eligibility, they apply for an ITIN on Form W-7 attached to that return.
• Spouse on a joint return. A U.S. citizen wants to file jointly with a nonresident spouse who has no SSN. The spouse applies for an ITIN so both can be identified on the return.
• Dependent abroad. A resident alien claims a dependent child who lives abroad and is not eligible for an SSN; the child needs an ITIN to be listed.
• Nonresident student. An international student receives a taxable scholarship and must file a return or claim a treaty benefit, using an ITIN under one of the W-7 exceptions.

In each case the ITIN does one job - it identifies the person on a federal tax filing. It does not change their status or grant any benefit beyond letting them meet their tax obligations.

Related Terms

• What is an EIN? - the 9-digit federal tax ID for businesses.
• ITIN vs. SSN - how the two individual numbers differ.
• How to get an ITIN - the step-by-step Form W-7 process.
• ITIN (glossary) - the one-line definition.
• Responsible party - the person who can use an ITIN on a business EIN application.
• How to form an LLC - the formation hub that ties these tax IDs together.

Frequently Asked Questions

Does an ITIN let me work legally in the U.S.?

No. The IRS states an ITIN does not authorize work, does not provide or change immigration status, and does not qualify you for Social Security benefits. It exists only for federal tax filing and reporting.

What does an ITIN look like?

It is a 9-digit number that always begins with 9 and is written like an SSN: 9XX-XX-XXXX. The IRS issues it; it is not an SSN or an EIN.

How much does an ITIN cost?

Nothing to file Form W-7. A Certifying Acceptance Agent may charge for document authentication, but IRS Taxpayer Assistance Centers provide that help for free.

Can I claim the Earned Income Tax Credit with an ITIN?

No. The IRS requires a valid Social Security number for the EITC. An ITIN does not qualify you, your spouse, or a child for that credit.

Do ITINs expire?

Yes. An ITIN not used on a federal tax return for three consecutive years expires on December 31 after the third year. You renew it by filing Form W-7 and checking "Renew an existing ITIN."

Can I get an ITIN without filing a tax return?

Usually no - you must attach a federal return to Form W-7. Limited exceptions (treaty benefits, scholarships, mortgage interest, property sales) let some people apply without one.

Is an ITIN the same as an EIN?

No. An ITIN identifies an individual; an EIN identifies a business. A person uses Form W-7; a business uses Form SS-4.

Sources

1. IRS - Individual Taxpayer Identification Number (definition, issued regardless of status, what it does not do, processing time).
2. IRS - Taxpayer Identification Numbers (TIN) (ITIN format "begins with 9," SSN vs. EIN vs. ITIN, no EITC).
3. IRS - About Form W-7 (application/renewal for ITIN, form title).
4. IRS - Instructions for Form W-7 (acceptable documents, passport as stand-alone, return requirement and exceptions, reason codes).
5. IRS - Form W-7 (PDF, Rev. Dec. 2024) (application-type boxes, reason categories a–h).
6. IRS - How to apply for an ITIN (three submission methods, Austin mailing address, CAA and TAC options).
7. IRS - How to renew an ITIN (three-year non-use expiration, information-return exception, renewal steps).
8. IRS - Who qualifies for the EITC (valid SSN required; ITIN does not qualify).
9. IRS - Earned Income Tax Credit (EITC) (credit overview).
10. IRS - Employer Identification Number (EIN identifies a business entity).
11. IRS - About Form SS-4 (business applies for an EIN).
12. IRS - Get an Employer Identification Number (EIN is free from the IRS).
13. Cornell Legal Information Institute - 26 U.S. Code § 6109, Identifying numbers (statutory basis; § 6109(i) ITIN provisions and expiration).

LegalGlass provides general information for educational purposes and is not a law firm or a substitute for advice from a licensed attorney or tax professional. This page is information, not advice. Laws, forms, and processing times change; verify current requirements with the IRS before acting.