Form W-7: ITIN application guide

Written by  Andrew Coleman, CPA

Last updated Feb 27, 2026

If you need to file a US tax return but are not eligible for a Social Security Number (SSN), you must apply for an Individual Taxpayer Identification Number (ITIN). An ITIN is a nine-digit tax processing number issued by the IRS to individuals who have a federal tax filing requirement but do not qualify for an SSN. This often includes US expats with foreign spouses, nonresident individuals with US-source income, and certain dependents of US taxpayers.

An ITIN is used strictly for tax reporting purposes and does not authorize employment or provide Social Security benefits. However, it allows you to file tax returns, claim eligible tax benefits, and remain compliant with US tax laws. This guide explains who qualifies, what documents are required, how to apply using W-7 form and instructions, and how to avoid common mistakes that can delay processing.

Who needs an ITIN?

You may need an ITIN if:

• You are a US expat with a foreign spouse who does not qualify for an SSN but will be included on your tax return.
• You are a non-resident foreign individual who needs to file a US tax return, e.g., earning rental income from US property.
• You are a dependent or spouse of a US citizen or resident alien and are required for tax reporting purposes.
• You are a foreign student, researcher, or visa holder with US tax obligations.
• You own a business in the US and need an ITIN for tax reporting.

Required supporting documents for W-7 form

To successfully complete your ITIN application, you need to verify both your identity and your foreign status. The IRS accepts two categories of documents.

Primary identification document

A valid passport is the only document that satisfies both requirements on its own – it proves your identity and your foreign status simultaneously. Submitting a passport is the simplest and most reliable option, and the IRS strongly recommends it.

Secondary documents (if you don't have a passport)

If you don't have a passport, you must submit two separate documents – one to prove identity and one to prove foreign status. The IRS accepts the following:

Medical records are accepted only for dependents under age 6, and school records are accepted only for dependents under age 24 — and they must meet the IRS content requirements (official/dated, signed, and recent term/care dates). Don’t present medical/school records as foreign status’ documents; use the IRS-approved identity/foreign status documents list (passport is the simplest single document when available).

NOTE! The IRS generally requires original documents or copies certified by the issuing agency. The IRS does not accept notarized copies. To avoid mailing originals, you can use an IRS Taxpayer Assistance Center (TAC) with ITIN services or a Certifying Acceptance Agent (CAA) to authenticate eligible documents (with some limitations, especially for dependents).

How to apply for an ITIN: Step-by-step guide

Applying for an individual taxpayer identification number is more straightforward than it might seem. Follow the steps below carefully, and your W7 ITIN application will be processed without unnecessary delays.

Step 1: Complete ITIN Form W-7

Download the latest Form W-7:

Fill out the form carefully, providing the following details:

• Your full legal name (exactly as it appears on your passport or official documents)
• Your US mailing address and foreign address
• Date of birth and country of citizenship
• US visa number (if applicable)
• The reason for applying for an ITIN (check the appropriate box on Form W-7)

Important: Common errors include misspelled names, incorrect addresses, and missing information, which can lead to application rejections.

Step 2: Gather supporting documents

To verify your identity and foreign status, you must provide original or certified copies of specific documents. A valid passport is the best option – it proves both your identity and your foreign status in one document. If you don't have a passport, you'll need two separate documents from the IRS-approved list.

Important: The IRS does not accept notarized copies – documents must be certified by the issuing authority.

Step 3: Attach a US tax return (if required)

Most first-time ITIN applicants must attach their U.S. federal tax return to Form W-7 (for example, Form 1040 or Form 1040-NR, depending on your filing situation). Attach Form W-7 to the front of the return. If you qualify for an IRS exception, you may submit Form W-7 without a tax return, but you must include the specific documentation required for that exception. This is because ITINs are issued primarily for tax filing purposes.

Some applicants can submit Form W-7 without attaching a tax return under specific IRS exceptions (for example, certain nonresident aliens claiming a tax treaty benefit, or certain situations involving U.S. withholding/information reporting). These exceptions have strict documentation requirements listed in the Form W-7 Exceptions Tables.’ If you’re claiming a treaty benefit, Form W-7 generally must include the treaty country and article number and you must provide the required supporting documentation described in the instructions

Important: If unsure, including a tax return helps avoid processing delays.

Step 4: Submit your ITIN application

Once your Form W-7 is complete and your documents are ready, you must submit your application using one of the IRS-approved methods. You can choose to mail your documents, work with a Certified Acceptance Agent (CAA), or visit an IRS Taxpayer Assistance Center (TAC). Each option has different requirements and levels of document security (see submission methods below).

Where to send W7 form?

You mail Form W-7 (with your tax return and original/certified ID documents, unless you’re using a CAA/TAC) to the IRS ITIN unit in Austin:

U.S. Postal Service (USPS):

Internal Revenue Service

ITIN Operation

P.O. Box 149342

Austin, TX 78714-9342

Private delivery service (FedEx/UPS/DHL, etc.):

Internal Revenue Service

ITIN Operation

3651 S. Interregional Hwy 35

Austin, TX 78741-0000

If you apply in person at an IRS TAC or through a Certifying Acceptance Agent, you generally don’t mail originals – they handle verification and submission steps per IRS rules.

Checking your ITIN application status

To track your application, call the IRS:

From the US: 1-800-829-1040

From outside the US: 1-267-941-1000

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How to submit Form W-7

Form W-7 cannot be filed online. You must choose one of the three submission methods below – each has its own tradeoffs, particularly when it comes to protecting your original identity documents.

1. Mail to the IRS ITIN Processing Center

Mailing is the most accessible option, but it comes with a real risk: you may need to send your original passport or other identity documents, which could be lost or delayed in transit. If you go this route, consider using a trackable courier service.

Internal Revenue Service ITIN Operation P.O. Box 149342 Austin, TX 78714-9342

Using a private courier service like FedEx or UPS? Send it to:

Internal Revenue Service ITIN Operation 3651 S. Interregional Hwy 35 Austin, TX 78741-0000

2. Use a Certified Acceptance Agent (CAA)

CAAs can verify documents, so you don't have to mail originals. This is the safest option if you are concerned about sending your passport by post. For dependents, CAAs can only verify passports and birth certificates (other dependent docs must be mailed). Find an IRS-authorized CAA here.

3. Visit an IRS Taxpayer Assistance Center (TAC)

Some IRS offices can verify your identity in person before processing your application. This is another way to avoid mailing original documents. Check office availability on the IRS website. TACs can’t authenticate school/medical records for dependents — those must be mailed with the ITIN package.

NOTE! Allow 7 weeks for the IRS to notify you about your ITIN application status. It can take 9–11 weeks if it’s tax season (January 15 to April 30) or if you applied from overseas.

ITIN renewal: What to do if your ITIN has expired

An ITIN expires if not used on a tax return for three consecutive years. This means that even if you previously had a valid individual taxpayer identification number, you may need to renew it before filing.

To renew an ITIN:

1. Fill out Form W-7 and check the renewal box.
2. Submit updated identification documents.
3. A tax return is not required unless filing at the same time.
4. Submit the renewal form via mail, CAA, or an IRS TAC.

An ITIN expires if it isn’t used on a U.S. federal tax return for 3 consecutive tax years (it expires on December 31 after the third year of non-use). You generally renew an ITIN when it needs to be included on a U.S. federal tax return. For spouses/dependents renewing to claim an allowable tax benefit, the ITIN must be shown on an attached federal return with the applicable schedule/form.

Common ITIN mistakes to avoid

Many ITIN applications are rejected due to simple mistakes. Following the Form W-7 instructions carefully and double-checking your documents before submission can prevent most of these issues.

Avoid the following errors:

• Missing supporting documents – A certified passport copy is the best option.
• Not using certified copies – A common mistake is sending a notarized copy, thinking it's acceptable, but the IRS only accepts certified copies from the issuing authority.
• Incorrect or incomplete Form W-7 – Ensure all fields are accurate before submission.
• Failing to attach a tax return – If required, your ITIN application will be rejected without it.

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