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Home > Guides > Faxing Form SS-4 for an EIN

How do I fax Form SS-4 to get an EIN?

Fill out Form SS-4, sign it, and fax it to the IRS number matching your location: 855-641-6935 if your business is in the 50 states or DC, or the international numbers if it is not. Include a return fax number on the form so the IRS can fax your EIN back, usually within about four business days. This is general information, not tax advice.

Which fax number do I use?

The IRS runs separate fax lines depending on where your business sits. Pick the wrong one and your application lands in the wrong queue:

Your business location	Fax Form SS-4 to
Principal business, office, or legal residence in the 50 states or DC	855-641-6935
No US residence or principal place of business, faxing from within the US	855-215-1627
No US residence or principal place of business, faxing from outside the US	304-707-9471

Two details people miss. First, put your own fax number on the form. The IRS returns the EIN by fax to the number you provide, and without one they cannot send it back to you. Second, the IRS notes these fax numbers can change without notice, so check the current SS-4 instructions on irs.gov before you send. The fax lines run 24 hours a day, seven days a week.

How does faxing compare to the other ways to apply?

Method	Speed	Best for
Online application	Immediate	US-based applicants with a Social Security or taxpayer ID number
Fax Form SS-4	EIN faxed back in about four business days	Applicants who cannot use the online tool, including foreign applicants
Mail Form SS-4	About four weeks	Anyone with time to spare
Phone (international applicants only)	Same call	Applicants outside the US with no US residence: 267-941-1099

Notice the gap: online is instant but only works if your principal place of business is in the US and you have a valid taxpayer ID. That is exactly why faxing matters. Foreign founders, entities without a US taxpayer ID for the responsible party, and anyone whose online application got rejected are the people for whom fax is the fastest realistic route.

What do I need before I fax?

A completed Form SS-4. Download the fillable PDF from irs.gov. It is designed to be suitable for faxing, so fill it in digitally rather than handwriting it: handwriting errors are a common reason applications stall.
A signature. An unsigned application is not valid. The right signer depends on the entity: an individual for a sole proprietorship, a principal officer for a corporation, an authorized member or officer for a partnership or LLC, a fiduciary for a trust or estate.
The responsible party's taxpayer ID. The form must name a real person in charge of the entity, with their Social Security, individual taxpayer, or employer identification number. Nominees are not authorized to apply.
A return fax number. As above: no return number, no EIN by return fax.
One application per day. The IRS limits EIN issuance to one per responsible party per day, whether you apply online, by phone, by mail, or by fax.

Why would I fax instead of applying online?

Most US-based founders should just apply online: it is free and immediate. Faxing earns its place in three situations. One, you are outside the US or lack a US taxpayer ID, which locks you out of the online tool entirely. Two, your online application was rejected (the infamous Reference 101 error usually means the IRS system found a conflict with your name or ID, and reapplying online rarely helps). Three, you are applying for certain entity types or through a third-party designee and want a paper trail with a dated fax confirmation showing exactly when the IRS received it.

A practical tip: keep the fax confirmation page with your copy of the signed SS-4. If the EIN does not arrive within the expected window, that confirmation is your proof of when and where you sent it, which makes the follow-up call to the IRS much shorter.

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