The IRS fax number for Form SS-4 is 855-641-6935. It is for a business or legal residence in one of the 50 states or the District of Columbia. With no residence or place of business in any state, the number is 855-215-1627 from inside the United States. From outside the United States it is 304-707-9471. All three were read on irs.gov on 2026-11-10.
This is not tax advice, and Fax for Agents is not part of the IRS. The IRS says its Fax-TIN numbers "may change without notice". Check the IRS page for Form SS-4 before you send.
What is the fax number for Form SS-4?
| Who uses it | Fax number | IRS page |
|---|---|---|
| Your principal business, office or agency, or your legal residence, is in one of the 50 states or the District of Columbia | 855-641-6935 | Where to file your taxes for Form SS-4 |
| You have no legal residence, principal place of business or principal office in any state, and you fax from within the United States | 855-215-1627 | The same page |
| You have no legal residence, principal place of business or principal office in any state, and you fax from outside the United States | 304-707-9471 | The same page |
Have the number? Send the form now for $2.49, the price as of 2026-11-12. Send a fax
The instructions for Form SS-4, revision 12/2025, give the same three numbers. They add that "Fax-TIN numbers can only be used to apply for an EIN". The line is open 24 hours a day, 7 days a week.
All three are US numbers and cost the same to fax. Which one applies to you is the IRS's rule.
Do you need to fax at all?
Often not. The IRS issues an EIN online at once when the application is approved. Its page says "You never have to pay a fee for an EIN."
The online application is open to you when all four of these are true, in the IRS's words:
- You are a domestic organization, formed or created in the United States or U.S. territories.
- Your principal place of business is in the U.S. or U.S. territories.
- You're the responsible party in control of the entity or its authorized representative.
- You have the responsible party's Social Security number (SSN) or individual taxpayer ID number (ITIN).
It is closed when the principal place of business is outside the United States. Then the IRS says to apply by phone, fax or mail. Applicants outside the United States can call 267-941-1099, Monday to Friday from 6:00 a.m. to 11:00 p.m. Eastern time. It is not a toll-free number.
Pick one route. The instructions say "Use only one method for each entity so you don't receive more than one EIN for an entity."
How long does an EIN by fax take?
About four business days. The instructions say "you can receive your EIN by fax generally within 4 business days". The IRS processing status page, dated 2026-11-06, said the same for a faxed Form SS-4.
Here is each route with the time the IRS gives for it:
- Online: the EIN is issued "immediately online" when the application is approved.
- Phone, for applicants outside the United States: the representative gives the number on the call.
- Fax: within 4 business days.
- Mail: "in approximately 4 weeks".
One limit holds on every route. The IRS issues one EIN per responsible party per day.
How does the IRS send the EIN back?
By fax, to the fax number you write on the form. The instructions say "Be sure to provide your fax number so the IRS can fax the EIN back to you."
This matters with any online fax service. The number in the header of a fax we send is a shared sending number. It takes no replies for you, so do not copy it onto the form.
To get the reply you need a number that receives faxes. In the Fax for Agents dashboard you can rent a US number from the prepaid wallet. It costs $2 a month plus $0.019 for each received page, as of 2026-10-28. The reply lands in your private inbox as a PDF. Release the number once you have the EIN, and the charge stops from the next month.
What should be on the form before you fax it?
Sign and date it. The instructions list who signs for each kind of applicant.
Write your return fax number on it.
If someone else applies for you, the Third Party Designee section has to be filled in and signed. The instructions say "You must complete the signature area for the authorization to be valid."
A foreign-owned U.S. disregarded entity that needs the EIN to file Form 5472 has its own wording for line 9a. Our post on Form 5472 and the pro forma Form 1120 quotes it.
How do I know the IRS got it?
A fax receipt shows that the pages were transmitted to the number. It does not show that the IRS assigned an EIN. The proof of that is the EIN itself, when it comes back.
The instructions name 800-829-4933 to verify a number or to ask about an application sent by mail. They name no status line for a faxed one.
The page on faxing to the IRS has the steps, the receipt in detail and the fax numbers for other forms.