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What Is an Individual Tax Identification Number (ITIN)?

An Individual Tax Identification Number, commonly called an ITIN, is a nine-digit number issued by the Internal Revenue Service (IRS). The number looks similar to a Social Security number and follows the same format: XXX-XX-XXXX. The IRS assigns ITINs to people who have a federal tax reporting requirement but cannot obtain a Social Security number.

The ITIN was created in 1996 to help the government track tax obligations and ensure proper filing of tax returns. According to IRS data, approximately 16 million ITINs are active in the United States. These numbers serve as tax identification for filing purposes, but they do not grant work authorization or change immigration status.

An ITIN functions specifically for tax purposes. A person with an ITIN can file federal tax returns, claim refunds, and report income to the government. However, an ITIN does not allow someone to work legally in the United States unless they already have proper work authorization through other means. The number is purely for tax identification and reporting.

The IRS issues ITINs to several categories of people. These include nonresident aliens who have U.S. source income, resident aliens, dependent family members, and spouses of U.S. citizens or residents. Some people use ITINs while in the process of obtaining a Social Security number. Others maintain an ITIN as their primary tax identifier for their entire time in the United States.

Understanding what an ITIN is—and what it is not—helps people make informed decisions about their tax situation. An ITIN is a tool for reporting income and filing taxes. It is not a form of identification for travel, not a work permit, and not proof of legal status in any way.

Practical Takeaway: An ITIN is a nine-digit number used only for federal tax purposes. If you have a federal tax requirement but no Social Security number, you may need to understand how to obtain and use an ITIN.

Who May Need an Individual Tax Identification Number

Various groups of people may have a reason to obtain an ITIN. Understanding whether your situation involves a federal tax requirement is the first step in determining whether an ITIN relates to your circumstances.

Nonresident aliens who earn U.S. source income represent one primary group that may need an ITIN. This includes people who live outside the United States but receive income from U.S. investments, rental property, or self-employment. For example, someone living in Canada who owns rental property in Florida and receives rental income must report that U.S. source income to the IRS. To file the required tax return, that person would need an ITIN.

Resident aliens—people who are lawfully in the United States but do not yet have a Social Security number—may also need an ITIN. This group includes some people on certain visa categories and those in the process of adjusting their immigration status. A resident alien with a job or other taxable income needs a way to report that income, and an ITIN serves that purpose.

Spouses of U.S. citizens and residents who do not have Social Security numbers may need an ITIN. U.S. tax law allows married couples to file joint tax returns. When one spouse does not have a Social Security number but the household has a federal tax filing requirement, an ITIN enables the non-citizen spouse to be included on the joint return. The IRS reports that in recent tax years, roughly 2 million tax returns included an ITIN.

Dependent family members who do not have Social Security numbers also may need an ITIN. Parents who claim children as dependents must provide a tax identification number for each dependent on their return. If a dependent does not have a Social Security number, the dependent needs an ITIN.

Self-employed individuals without Social Security numbers may need an ITIN to report business income. Anyone operating a business and earning more than $400 in self-employment income must file a tax return with the IRS. A self-employed person without a Social Security number uses an ITIN for this purpose.

Practical Takeaway: Several categories of people may have a federal tax requirement that necessitates an ITIN. These include nonresident aliens with U.S. income, certain resident aliens, spouses of U.S. citizens, dependents, and self-employed individuals.

How the ITIN Application Process Works

The process for obtaining an ITIN involves submitting a completed Form W-7 to the IRS along with required supporting documents. Understanding the steps and requirements can help clarify what information and paperwork are needed.

The first step is obtaining Form W-7, which is the Application for IRS Individual Identification Number. This form is available directly from the IRS website at irs.gov, and it contains instructions specific to different situations. The form itself is straightforward and asks for basic information including name, date of birth, address, and country of citizenship.

After completing Form W-7, a person must gather supporting documents. The IRS requires proof of identity and proof of residency (if applicable to the person's situation). Acceptable forms of identification include a passport, national identification card, or other government-issued identification document. Documents must be originals or certified copies—photocopies are not accepted unless certified by the issuing agency.

The completed form and documents can be submitted in several ways. One option is mailing the materials directly to the IRS address specified on the Form W-7 instructions. Another option is working with a tax professional, accountant, or IRS-authorized representative who can submit the materials on a person's behalf. Some community organizations and nonprofit agencies also help people complete and submit ITIN applications.

The IRS processes ITIN applications and typically takes several weeks to several months to issue a number. Processing times vary depending on the volume of applications the IRS receives and whether the application is complete. A complete application with all required documents processes faster than an incomplete one.

Once the IRS issues an ITIN, the person receives a letter with the number. This letter serves as proof that the ITIN was issued. The person can then use the ITIN on tax returns, W-4 forms, and other tax-related documents.

It is important to understand that submitting an ITIN application does not itself trigger any changes to immigration status or create any record with immigration authorities. The ITIN is issued by the IRS for tax purposes only. The application process is a tax administration process, separate from immigration processes.

Practical Takeaway: Obtaining an ITIN involves completing Form W-7, gathering proof of identity and residency, and submitting these materials to the IRS by mail or through an authorized representative.

Using Your ITIN for Tax Purposes

Once a person has an ITIN, they can use it to file federal tax returns and handle other tax-related matters. Understanding the proper use of an ITIN helps ensure accurate tax reporting.

The primary use of an ITIN is filing a federal income tax return. A person with an ITIN completes Form 1040 or another appropriate tax return form, enters their ITIN where the form requests a tax identification number, and reports all income subject to U.S. taxation. Income that must be reported includes wages from a job, self-employment income, investment income, rental income, and other sources as defined by tax law.

An ITIN also allows a person to claim refundable tax credits. The Earned Income Tax Credit (EITC) and the Additional Child Tax Credit (CTC) are refundable credits, meaning that if the credits exceed the tax owed, the IRS sends the person a refund. However, to claim these credits with an ITIN, specific requirements must be met. For example, the EITC has income limits and work requirements. The IRS provides detailed information about credit requirements on its website.

A person with an ITIN can also use it to claim a dependent. When filing a tax return, a person lists dependents and provides a tax identification number for each dependent. This allows the IRS to prevent duplicate claims and ensure accurate reporting. A dependent can have either a Social Security number or an ITIN.

An ITIN is used on Forms W-4, which are submitted to employers or financial institutions. When a person with an ITIN starts a job, they complete a