Updated April 2026
ITIN Resources: Official IRS Links & Tools 2026
Every official IRS resource you need for your ITIN application and tax filing, organized in one place. This page links to IRS forms, instructions, locator tools, phone numbers, tax treaty tables, and state tax agency websites. All links go directly to official government sources. Bookmark this page as your go-to reference for ITIN-related resources.
IRS Forms and Instructions
Direct links to the IRS forms and instructions most commonly needed by ITIN applicants and holders.
Form W-7: Application for ITIN
The primary form for applying for or renewing an ITIN. Includes instructions for all 5 exception categories.
irs.gov/forms-pubs/about-form-w-7 →Form 1040-NR: US Nonresident Alien Income Tax Return
The tax return form for nonresident aliens with US-source income. Most commonly attached to Form W-7 for ITIN applications.
irs.gov/forms-pubs/about-form-1040-nr →Form W-8BEN: Certificate of Foreign Status
Filed by foreign individuals to certify non-US status and claim tax treaty benefits on US-source income.
irs.gov/forms-pubs/about-form-w-8-ben →Form SS-4: Application for EIN
Used by ITIN holders to apply for an Employer Identification Number for their US business. Submit by mail or fax.
irs.gov/forms-pubs/about-form-ss-4 →Form 4868: Extension of Time to File
Grants an automatic 6-month extension to file your tax return (until October 15). Does not extend the payment deadline.
irs.gov/forms-pubs/about-form-4868 →Form 5472: Foreign-Owned US Corporation Report
Required for foreign-owned single-member LLCs. Filed annually with a pro forma Form 1120.
irs.gov/forms-pubs/about-form-5472 →IRS ITIN Information Pages
Official IRS pages with detailed ITIN information, eligibility requirements, and application instructions.
IRS ITIN Main Page
Overview of ITIN purpose, eligibility, and application process.
irs.gov/individuals/individual-taxpayer-identification-number →How to Apply for an ITIN
Step-by-step IRS guide for new ITIN applications and renewals.
irs.gov/individuals/how-do-i-apply-for-an-itin →ITIN Acceptance Agent Program
Information about the CAA program, how to find an agent, and agent responsibilities.
irs.gov/individuals/acceptance-agent-program →IRS Locator Tools
Find IRS offices, free tax preparation sites, and other in-person assistance near you.
IRS Taxpayer Assistance Center Locator
Find the nearest IRS walk-in office. Enter your ZIP code for addresses, hours, and services available.
irs.gov/help/contact-your-local-irs-office →VITA Site Locator
Find free tax preparation help through the Volunteer Income Tax Assistance program. Available for taxpayers earning $67,000 or less.
irs.gov/individuals/free-tax-return-preparation-for-qualifying-taxpayers →Acceptance Agent Lookup
Search for IRS-authorized Acceptance Agents and Certifying Acceptance Agents by location.
irs.gov/individuals/acceptance-agent-program →IRS Phone Numbers
Key phone numbers for ITIN applicants and holders. All US numbers are toll-free unless noted.
| Purpose | Phone Number | Hours |
|---|---|---|
| ITIN status and general inquiries | 1-800-829-1040 | Mon-Fri, 7 AM to 7 PM |
| TAC appointment scheduling | 1-844-545-5640 | Mon-Fri, 7 AM to 7 PM |
| International callers | 1-267-941-1000 (not toll-free) | Mon-Fri, 6 AM to 11 PM ET |
| Tax forms and publications | 1-800-829-3676 | Mon-Fri, 7 AM to 7 PM |
| Report tax fraud or scams | 1-800-366-4484 (TIGTA) | 24/7 |
| Social Security Administration | 1-800-772-1213 | Mon-Fri, 8 AM to 7 PM |
Tax Treaty Resources
US tax treaties reduce or eliminate double taxation for residents of treaty countries. These resources help ITIN holders understand and claim treaty benefits.
US Tax Treaties A to Z
Complete list of US tax treaties by country. Each entry links to the full treaty text and technical explanations.
irs.gov/businesses/international-businesses/united-states-income-tax-treaties-a-to-z →Publication 901: US Tax Treaties
Summary tables of treaty withholding rates by country and income type (dividends, interest, royalties, pensions).
irs.gov/publications/p901 →Publication 519: US Tax Guide for Aliens
Comprehensive guide for determining residency status, filing requirements, and tax obligations for foreign nationals.
irs.gov/publications/p519 →State Tax Agency Links (Top 10 States)
State tax filing requirements vary. The following states have the highest ITIN-filing populations. Visit your state's tax agency website for state-specific forms, instructions, and payment information.
| State | Tax Agency | Website | State Income Tax |
|---|---|---|---|
| California | Franchise Tax Board | ftb.ca.gov | 1% to 13.3% |
| Texas | Comptroller of Public Accounts | comptroller.texas.gov | None |
| New York | Dept. of Taxation and Finance | tax.ny.gov | 4% to 10.9% |
| Florida | Dept. of Revenue | floridarevenue.com | None |
| Illinois | Dept. of Revenue | tax.illinois.gov | 4.95% flat |
| New Jersey | Division of Taxation | nj.gov/treasury | 1.4% to 10.75% |
| Arizona | Dept. of Revenue | azdor.gov | 2.5% flat |
| Georgia | Dept. of Revenue | dor.georgia.gov | 1% to 5.49% |
| North Carolina | Dept. of Revenue | ncdor.gov | 4.5% flat |
| Virginia | Dept. of Taxation | tax.virginia.gov | 2% to 5.75% |
Key IRS Publications for ITIN Holders
These free IRS publications provide detailed information relevant to ITIN holders, nonresident aliens, and international tax situations.
Publication 1915: Understanding Your ITIN
The IRS's own guide to ITINs, including purpose, application process, renewal, and frequently asked questions.
Download Publication 1915 (PDF) →Publication 519: US Tax Guide for Aliens
Comprehensive guide covering residency determination, filing requirements, income types, deductions, and credits for foreign nationals.
irs.gov/publications/p519 →Publication 515: Withholding on Nonresident Aliens
Details withholding rates, reporting requirements, and treaty benefits for payments to nonresident aliens and foreign entities.
irs.gov/publications/p515 →Publication 901: US Tax Treaties
Summary of withholding rates under US income tax treaties. Tables by country and income type.
irs.gov/publications/p901 →itin.so Guides and Tools
In addition to official IRS resources, itin.so provides comprehensive guides, calculators, and tools to help you navigate the ITIN process.
W-7 Form Guide
Line-by-line instructions for completing Form W-7.
Accepted Documents List
All 13 IRS-accepted identification documents.
ITIN Timeline Guide
Complete processing timeline with seasonal variations.
Cost Calculator
Compare DIY, Standard, and Express costs.
Timeline Tracker
Track your application progress week by week.
ITIN vs SSN Checker
Determine which tax ID you need.
ITIN Glossary
30+ tax terms explained in plain English.
CAA Guide
What is a Certifying Acceptance Agent and why use one.
Ready to Apply for Your ITIN?
Professional ITIN preparation with Certifying Acceptance Agent verification. Standard ($297) or Express ($297). Tax return preparation included.
Start Your ITIN ApplicationFrequently Asked Questions About ITIN Resources
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Apply for Your ITIN TodayLearn more about ITIN terminology in our ITIN Glossary.