IRS Form W-7 Instructions 2026: Line-by-Line ITIN Application Guide

What Is IRS Form W-7 and Who Needs to File It?

Form W-7 is the IRS application for an Individual Taxpayer Identification Number. Anyone who has a US federal tax obligation but is not eligible for a Social Security Number must file Form W-7 to obtain an ITIN. The form is 2 pages long and requires supporting identification documents.

5 groups of people file Form W-7:

1. Non-resident aliens filing a US tax return. This is the most common reason, covering 70% of W-7 applications.
2. Spouses of US citizens or residents claimed as exemptions on joint returns. See our ITIN for spouses guide.
3. Dependents of US citizens or residents claimed on tax returns.
4. Non-resident aliens claiming tax treaty benefits to reduce withholding on US-source income.
5. Foreign nationals with US reporting requirements such as mortgage interest statements or partnership income.

Form W-7 is available for free at irs.gov. The current revision date is October 2023. The IRS periodically updates the form, so always download the latest version before applying.

How Do You Fill Out Lines 1a and 1b: Name?

Lines 1a and 1b capture your legal name exactly as it appears on your identification documents. Mismatches between your W-7 name and your passport or national ID are the second most common rejection reason.

Line 1a: Name (as shown on your tax return)

Enter your first name, middle name (or initial), and last name. This name must match exactly what you enter on your tax return (Form 1040-NR or Form 1040). Use only English alphabet characters. If your passport uses non-Latin characters, use the romanized version shown in the machine-readable zone at the bottom of your passport data page.

Line 1b: Name at birth if different

Complete Line 1b only if your birth name differs from your current legal name. This applies to name changes due to marriage, court order, or other legal processes. If your birth certificate shows a different name than your passport, enter the birth certificate name here. Leave blank if your name has not changed.

How Do You Complete Line 2: Mailing Address?

Line 2 is your mailing address where the IRS sends your ITIN assignment notice (CP565) and any correspondence. You can use a US or foreign address. The IRS mails to this address, so accuracy is critical.

Line 2: Street address, apartment number, city, state/province, country, ZIP

Enter your complete mailing address. If you live outside the US, include your country name and foreign postal code. Do not abbreviate the country name. Write “United Kingdom” not “UK.” The IRS processes mail to international addresses, but delivery takes 4 to 8 weeks longer than US addresses. If you have a US address available (through a registered agent, accountant, or family member), using it speeds up delivery.

There is also a “Foreign address” section below the main address lines. If your permanent residence is different from your mailing address, enter your home country address in the foreign address section. This is common for applicants using a US mailing address but living abroad.

What Information Goes on Line 3: Birth Information?

Line 3 captures your date of birth, country of birth, city and state/province of birth, and gender. All fields are mandatory. The IRS uses this information with your identification documents to verify your identity.

Line 3a: Date of birth (month/day/year)

Use the US date format: MM/DD/YYYY. This catches many international applicants who use DD/MM/YYYY. Writing 05/03/1990 means May 3, 1990 in US format, not March 5, 1990. Verify your date format matches US conventions before submitting.

Line 3b: Country of birth

Enter the country name as it appears on your birth certificate or passport. Use the current country name. If your birth country no longer exists (e.g., Yugoslavia, USSR), use the current country name for that territory.

Line 3c: City and state/province of birth

Enter the city and state or province where you were born. This must match your birth certificate or passport. If your passport does not show a birth city, enter the city from your birth certificate.

Line 3d: Gender

Check Male or Female. This must match the gender shown on your primary identification document. If your passport shows a different gender than your birth certificate due to a legal change, use the gender on your passport.

How Do You Fill In Line 4: Country of Citizenship?

Line 4 asks for your country or countries of citizenship. Enter every country where you hold citizenship. Dual citizens list both countries. This field establishes your foreign status, which is a core requirement for ITIN eligibility.

US citizens and US nationals are not eligible for ITINs. If you are a US citizen, you must apply for a Social Security Number instead. The IRS rejects W-7 applications listing the United States as the country of citizenship unless accompanied by documentation showing dual citizenship with a foreign country and ineligibility for an SSN.

What Goes on Line 5: Other Tax Identification Numbers?

Line 5 asks whether you have any existing US or foreign taxpayer identification numbers. Enter any prior ITIN, SSN (if previously held), or foreign tax ID number. This helps the IRS prevent duplicate ITIN issuance and connect your records.

Line 5a: Previous ITIN or SSN

If you previously held an ITIN that expired or was deactivated, enter it here. The IRS may reissue the same number. If you ever had an SSN (even if it is no longer valid), enter it. The IRS uses this to link your tax history.

Line 5b: Foreign tax identification number

Enter your tax ID from your home country. Examples: National Insurance Number (UK), Tax File Number (Australia), PAN (India), RFC (Mexico), CPF (Brazil). This is optional but recommended. It helps the IRS verify your identity and is used for tax treaty claims.

How Do You Choose the Correct Reason Code on Lines 6a Through 6g?

Line 6 is the most critical section of Form W-7. You must check exactly one box from 6a through 6g. Selecting the wrong reason code causes 25% of all W-7 rejections. Each code has specific documentation requirements.

Line 6a: Nonresident alien filing a US federal tax return

Check this box if you are filing a US tax return (Form 1040-NR or Form 1040). This is the most common reason, used by 70% of applicants. You must attach your completed tax return to Form W-7. Write “ITIN TO BE REQUESTED” in the SSN field of your tax return. The IRS processes your W-7 first, assigns your ITIN, then processes your tax return.

Line 6b: Nonresident alien claiming a tax treaty benefit

Check this box if you are not filing a tax return but need an ITIN to claim reduced withholding under a US tax treaty. You must enter the treaty country and article number. Attach a completed Form W-8BEN or Form 8233 as supporting documentation. This exception allows W-7 filing without a tax return.

Line 6c: Nonresident alien student, professor, or researcher

For F-1, J-1, M-1, or Q-1 visa holders claiming a tax treaty exemption on scholarship or fellowship income. Attach a letter from your educational institution confirming your enrollment status and visa type. Enter the treaty country and specific article number.

Line 6d: Dependent of a US citizen or resident

For dependents claimed on the tax return of a US citizen or resident alien. The person claiming you must enter their SSN or ITIN on your W-7. Attach documentation proving the relationship (birth certificate, adoption decree, or court order).

Line 6e: Spouse of a US citizen or resident

For spouses filing jointly with a US citizen or resident. The US citizen spouse must enter their SSN on your W-7. Attach a marriage certificate. This is the second most common reason code, used by approximately 20% of applicants. Learn more in our ITIN for spouses guide.

Line 6f: Third-party withholding or reporting

For individuals who need an ITIN because a US entity requires it for reporting purposes. This includes passive income recipients (dividends, interest, royalties) where the payer must report to the IRS on Form 1042-S. Attach the Form 1042-S or a letter from the withholding agent.

Line 6g: Other

For situations not covered by 6a through 6f. You must attach a detailed explanation of why you need an ITIN. Common uses include mortgage interest reporting requirements and state tax obligations. The IRS scrutinizes 6g applications more closely, so provide thorough documentation.

What Supporting Documents Does Form W-7 Require?

The IRS accepts 13 types of identification documents to prove identity and foreign status. A valid passport is the only single document that satisfies both requirements. Without a passport, you need at least 2 documents from this list:

All documents must be current (not expired) at the time of submission. The IRS rejects applications with expired passports or IDs. If your passport expires within 30 days, renew it before submitting Form W-7.

How Do You Complete the Signature and Delegate Sections?

The signature section is on page 2 of Form W-7. Sign and date the form. If you are applying for a dependent or minor child, the parent or legal guardian signs. The signature must be handwritten; the IRS does not accept electronic signatures on Form W-7.

Delegate Section (Acceptance Agent)

If you use a Certifying Acceptance Agent (CAA), the agent completes the Delegate section. The CAA enters their name, CAA number, PTIN, address, and signature. The CAA attaches Form W-7(COA) — Certificate of Accuracy — confirming they verified your original documents. Using a CAA means you keep your original documents and never mail them to the IRS.

Phone Number

Enter a phone number where the IRS can reach you. Include the country code for international numbers. The IRS rarely calls applicants, but providing a working number speeds resolution if they have questions about your application.

What Are the 3 Ways to Submit Form W-7?

You can submit Form W-7 through 3 methods. Each has different processing times and document requirements.

1. Mail to the IRS ITIN Unit

Mail your completed W-7, tax return, and original identification documents (or certified copies) to the Austin, TX address. Processing takes 7 to 11 weeks. Original documents are returned within 60 days of receipt. This method is free but requires mailing original documents. Use USPS certified mail or a tracked private carrier.

2. Apply through a Certifying Acceptance Agent

A CAA verifies your identity documents in person or via a secure process, certifies copies, and submits on your behalf. You keep your originals. Processing time is the same 7 to 11 weeks, but you eliminate the risk of lost documents. itin.so is a CAA-authorized service that handles the entire process. See our ITIN application service starting at $297.

3. Visit an IRS Taxpayer Assistance Center

The IRS has approximately 380 Taxpayer Assistance Centers (TACs) in the US. Walk in with your completed W-7, tax return, and original documents. The TAC agent verifies your documents on-site and returns them immediately. Processing still takes 7 to 11 weeks, but you avoid mailing originals. Appointments are recommended.

What Are the 7 Most Common Form W-7 Mistakes?

These 7 errors cause the majority of W-7 rejections. Avoid every one to ensure your application processes on the first submission.

1. Name mismatch. Your Line 1a name does not match your passport or tax return. Use your exact legal name on all documents.
2. Wrong date format. Using DD/MM/YYYY instead of US format MM/DD/YYYY on Line 3a. The IRS uses US date conventions.
3. Missing tax return. Filing with reason code 6a but forgetting to attach your Form 1040-NR or Form 1040.
4. Expired documents. Submitting an expired passport or national ID. All documents must be current at the time of filing.
5. Wrong reason code. Checking the incorrect box on Line 6 or checking multiple boxes. Select exactly one reason code.
6. Notarized copies instead of certified copies. The IRS accepts only original documents or copies certified by the issuing agency. Notarized copies are rejected.
7. Missing signature. Forgetting to sign and date page 2. Unsigned W-7 forms are automatically rejected.

For a comprehensive list, see our ITIN rejection reasons guide.

What Happens After You Submit Form W-7?

The IRS follows a 4-step process after receiving your Form W-7 application.

1. Document review (1 to 2 weeks). The IRS ITIN Unit in Austin, TX verifies your identification documents against your W-7 information.
2. Application processing (4 to 8 weeks). The IRS checks for duplicate ITINs, verifies your eligibility, and processes your reason code documentation.
3. ITIN assignment or rejection. If approved, the IRS assigns your 9-digit ITIN (format: 9XX-XX-XXXX) and mails your CP565 notice. If rejected, you receive a letter explaining why.
4. Tax return processing. After ITIN assignment, the IRS processes the tax return you attached to your W-7. This adds 2 to 4 additional weeks for refund processing.

Total time from submission to ITIN in hand: 7 to 11 weeks for the ITIN, plus 2 to 4 weeks for tax return processing and refund issuance. Track your application by calling the IRS at 1-800-829-1040 after 7 weeks.