Fax Form SS-4 to Get an EIN: IRS Numbers, Steps, and Follow-Up

To fax Form SS-4 to the IRS from any of the 50 states or the District of Columbia, send it to 855-641-6935. Under the IRS Fax-TIN program, you can expect an Employer Identification Number back by fax within about four business days, provided you included a return fax number and the form is complete.¹²

IRS Fax Numbers for Form SS-4

The right number depends on where the business (or the individual applicant) is located. Sending to the wrong number will delay processing.

Principal business, office, or agency in one of the 50 states or D.C.: 855-641-6935
No U.S. principal place of business, faxing from inside the U.S.: 855-215-1627
No U.S. principal place of business, faxing from outside the U.S.: 304-707-9471

These numbers can change. Verify the current ones on IRS.gov or in the latest Form SS-4 instructions before you send.¹

One boundary worth naming: if the responsible party has a Social Security number or ITIN and your principal place of business is in the U.S., the online EIN application issues a number immediately. Faxing is the right route when the online tool doesn’t work for you, typically because the responsible party lacks an SSN or ITIN or the business is based outside the United States.³

Get the Form Right Before You Send It

Most fax rejections come from a handful of fields. Fix these before the form goes through the machine.

Legal Name and Entity Type

The legal name on Line 1 must match your formation documents exactly, including suffixes like “Inc.” or “LLC.” A mismatch between the SS-4 and what’s on file with your state is one of the fastest ways to trigger a rejection. The entity type you select on Line 9a should reflect your actual legal structure; checking the wrong classification box creates downstream problems with your tax filings that are harder to unwind than to prevent.²

Responsible Party (Lines 7a–7b)

The responsible party is the individual who owns or controls the entity and manages its funds and assets. With one narrow exception for government entities, this must be an actual person, not another business.⁴ Enter that person’s SSN or ITIN on Line 7b. If the responsible party is a foreign individual who has neither and can’t get either, enter “foreign” or “N/A.” Sole proprietors use their own SSN or ITIN unless they’re nonresident aliens with no effectively connected U.S. income. For estates, use the decedent’s SSN or ITIN.²

Two Address Sections With Different Rules

Lines 4a–4b are your mailing address and can be a P.O. box. Lines 5a–5b are the physical location of the business and cannot be a P.O. box.²

Lines People Leave Blank

Line 10 (reason for applying) is required and does not accept “N/A”; check exactly one box. Line 16 (principal activity) needs a selection, and Line 17 needs a written description of your business. The IRS won’t issue an EIN if any of these are blank.⁵

Signature

The right signer depends on the entity: the individual for a sole proprietorship, a principal officer for a corporation, an authorized member or officer for a partnership or other organization, and the fiduciary for a trust or estate. Foreign applicants may have any authorized person sign. An unsigned form won’t be processed.⁵

Third-Party Designee

If you want your accountant or attorney to receive the EIN for you, name them in the third-party designee section. They’ll receive the EIN by the method you used to apply, but the official notice still goes to the taxpayer’s address by mail. The designee’s authority is narrow: they can receive the EIN and answer IRS questions about how the form was completed, and their authorization ends once the IRS assigns and releases the number. The designee section is only valid if the signature area is also completed.⁵

Sending the Fax

A traditional fax machine works, and so does any online fax service that lets you upload the completed form. Either way:

If any part of the form is handwritten, use dark ink and write clearly. Fax transmission degrades image quality, and a smudged SSN or business name is enough to sideline the application.
Include a cover sheet with your name, a contact phone number, and the return fax number you want the IRS to use for your EIN.
Save the transmission confirmation report. That’s your proof of sending if the IRS later says nothing arrived.

Sending during evenings or weekends may help you avoid busy signals on the IRS line, though it isn’t guaranteed.

After You Fax

Expect the EIN by return fax within four business days, so long as you included a return fax number.² Separately, the IRS mails the formal confirmation letter (CP 575) to the business address on the form. It typically arrives several weeks later and is the official record of your EIN. Keep it. Banks, creditors, and state agencies sometimes ask for it, and the IRS only issues the original once.

If Your EIN Doesn’t Come Back

If more than a week has gone by, call the IRS Business and Specialty Tax Line at 800-829-4933, open Monday through Friday, 7:00 a.m. to 7:00 p.m. local time (Alaska and Hawaii follow Pacific time). After verifying your identity, a representative can provide the EIN by phone or fax you a 147C verification letter.⁶

If a return or tax deposit is due before your EIN arrives, don’t substitute your personal SSN. Write “Applied For” and the date you submitted the SS-4 in the space where the EIN would go. For tax deposits, mail the payment to the IRS service center for your filing area, payable to “United States Treasury,” and include your name as shown on the SS-4, your address, the type of tax, the period covered, and the date you applied.²

1
Internal Revenue Service. Where to File Your Taxes for Form SS-4
2
Internal Revenue Service. Instructions for Form SS-4 (12/2025)
3
Internal Revenue Service. Get an Employer Identification Number
4
Internal Revenue Service. Responsible Parties and Nominees
5
Internal Revenue Service. Instructions for Form SS-4
6
Internal Revenue Service. Telephone Assistance Contacts for Business Customers