IRS Fax Numbers Directory 2026: Verified Numbers for SS-4, 5472, and 7004

Finding the correct Internal Revenue Service (IRS) fax number can be difficult because the agency operates specialized, decentralized intake units across multiple processing campuses. Sending a form to the wrong fax line or dialing an outdated number results in dropped submissions, processing backlogs, or statutory non-compliance.

Below is the verified directory of official IRS fax numbers for 2026, covering federal business registrations, foreign-owned entity disclosures, corporate extensions, and regional authorizations.

Verified IRS Fax Numbers Table

The numbers below are published by the IRS for public submission of specific federal forms and applications.

Notice: The IRS periodically updates geographic routing rules and regional center assignments. Senders should verify specific form instructions at IRS.gov prior to transmission.

Form-by-Form Breakdown and Dialing Guidelines

+-------------------------------------------------------------+
|                IRS FAX ROUTING AT A GLANCE                  |
+-------------------------------------------------------------+
| Form SS-4 (US Business in 50 States/DC)  --> 855-641-6935   |
| Form SS-4 (No US Residence, In US)       --> 855-215-1627   |
| Form SS-4 (International / Outside US)   --> 304-707-9471   |
| Form 5472 / 7004 (Foreign-Owned DE LLC)  --> 855-887-7737   |
| Form 1040 (Standard Annual Returns)      --> CANNOT FAX     |
+-------------------------------------------------------------+

1. Form SS-4 (Employer Identification Number)

If your business cannot use the online EIN Assistant—for example, if the responsible party does not have an SSN or ITIN—Form SS-4 must be submitted by fax.

• 50 US States and DC (
  ): Use this toll-free line if the applicant entity has a legal residence, principal place of business, or office located within any of the 50 US states or the District of Columbia.
• No US Legal Residence, Sending From Inside the US (
  ): Use this toll-free line if the business or responsible party has no legal residence in the US but the transmission originates from within the US.
• International Senders Outside the US (
  ): Use this direct-dial number when applying from abroad. Senders dialing internationally should format the number as
  .
• Response Protocol: Ensure Line 18 of Form SS-4 includes an active return fax number. The IRS will transmit the official EIN confirmation notice directly to that number.
• Assisted Service: Use SingleFax EIN by Fax for $9.99. We generate the compliant SS-4, transmit it to the Fax-TIN unit, allocate a 90-day return number, and forward the IRS confirmation letter to your email. Learn more in our complete Form SS-4 application guide.

2. Form 5472 and Pro Forma Form 1120 (Foreign-Owned US Disregarded Entities)

Under Treasury Regulation § 1.6038A-2, US single-member LLCs owned by non-US persons must file Form 5472 attached to a pro forma Form 1120.

• Verified Fax Line (
  ): Transmit the complete packet directly to the IRS Ogden PIN Unit.
• Technical Standards: Scan at 300 DPI or higher in high-contrast black and white. The top margin of Form 1120 must state "Foreign-owned U.S. DE".
• Statutory Penalty: Failure to file timely or filing inaccurate information carries a $25,000 penalty per form, per year.
• Automated Filing Tool: Prepare and transmit your documentation using the SingleFax Form 5472 tool for $29.99. For step-by-step instructions, see our guide on how to file Form 5472 by fax.

3. Form 7004 (Automatic 6-Month Corporate Extension)

If a foreign-owned disregarded entity needs additional time beyond the April 15 deadline to gather transaction records for Form 5472:

• Verified Fax Line (
  ): Fax Form 7004 to the same Ogden line used for Form 5472.
• Form Code: Enter Code
  on Part I, Line 1.
• Filing Window: Form 7004 must be transmitted on or before the return's original due date (April 15 for calendar-year entities). It extends the filing deadline to October 15.
• Online Filing: Submit your extension in minutes via SingleFax Form 7004 filing for $4.99. Review the complete walkthrough in our Form 7004 extension guide.

4. Forms Requiring Regional IRS Verification

Certain IRS forms do not use a single nationwide fax number. Instead, the agency divides processing by geographic region:

• Form 2848 (Power of Attorney): Routed to regional Centralized Authorization File (CAF) units. Filers must verify their state's active CAF line on IRS.gov Form 2848. Wet-ink signatures are strictly required.
• Form 4506-T (Transcript Requests): Transcripts are processed by regional RAIVS centers. Verify the specific fax number for your state in the IRS Form 4506-T instructions.
• Form 2553 (S-Corporation Elections): S-Corp elections are routed to either Ogden, UT or Kansas City, MO depending on the principal business state. Check current routing on IRS.gov Form 2553.

What Forms You CANNOT Fax to the IRS

Standard annual tax returns cannot be filed via fax. This includes:

• Form 1040, 1040-SR, and 1040-NR (Individual Income Tax Returns)
• Form 1120 (Standard C-Corporation Income Tax Returns)
• Form 1065 (Partnership Returns)
• Form 1120-S (S-Corporation Returns)

The IRS tax processing pipeline is not configured to accept standard tax returns from fax queues. Attempting to fax an annual return will result in the document being discarded without notice, leading to late-filing penalties.

The only exception is when an individual IRS revenue agent, appeals officer, or formal written notice explicitly provides a caseworker fax number and requests documents for an active examination or audit.

For full details, read Can You Fax a Tax Return to the IRS?.

Best Practices When Faxing the IRS

To prevent technical transmission failures and administrative delays:

1. Dialing Format: For US toll-free numbers (
   ), use standard 10-digit dialing (
   ). For international numbers (
   ), append the US country code (
   ).
2. Handle Busy Signals: IRS fax lines experience high volume, especially during peak tax filing periods (March, April, and October). Using an automated cloud fax provider ensures automatic retry attempts until a successful telecom handshake is achieved.
3. Save Transmission Confirmation: Always archive your fax transmission receipt. The receipt provides timestamped evidence showing total pages delivered and the receiving terminal identifier, establishing legal proof of timely filing.

Transmit IRS Documents with SingleFax

SingleFax provides pay-per-use, secure document transmission tailored for IRS workflows:

• General Document Faxing: Upload and send single tax documents starting at $0.99 for up to 10 pages at Send or Receive a Fax.
• EIN by Fax: Complete your Form SS-4 and receive your IRS assignment letter for $9.99 at Get EIN.
• Form 5472 Filing: Validate and transmit your pro forma 1120 and Form 5472 for $29.99 at File Form 5472.
• Form 7004 Extension: Secure an automatic 6-month extension for $4.99 at File Form 7004.

Related Guides

• How to Fax the IRS in 2026 (Forms, Numbers, What You Can't Fax)
• How to Apply for an EIN by Fax (Form SS-4 Guide)
• How to File Form 5472 by Fax for Foreign-Owned US LLCs
• Form 7004 Extension for Form 5472: How to Fax the IRS
• Can You Fax a Tax Return to the IRS?
• IRS and State Forms You Can Still Fax in 2026

Disclaimer: SingleFax provides secure document transmission services and automated document generation workflows. SingleFax is not a certified public accounting firm or law firm, and the information in this directory does not constitute tax, legal, or accounting advice. Always consult a qualified tax professional for entity-specific compliance.