Get an EIN by Fax in Four Business Days

Fax Form SS-4 to 855-641-6935 if your entity’s legal residence, principal place of business, or principal office is in one of the 50 states or Washington, DC. Entities with no U.S. state or DC residence fax to 855-215-1627 from inside the United States, or 304-707-9471 from outside the country. The Fax-TIN service runs around the clock, and the IRS generally faxes back your EIN within about four business days, provided you include a working return fax number.

TL;DR:

Using the correct IRS fax number depends on your entity’s legal residence, principal place of business, or office location, not your physical location when faxing.

Online EIN applications are faster but only available for entities with U.S. or territorial addresses and a responsible party with a valid taxpayer ID.

Before faxing, verify the latest fillable SS-4 form, ensure all sections are complete and signed, and confirm your return fax number is active to avoid delays.

Testing the return fax line before sending and keeping all confirmation records significantly reduces the risk of non-receipt or processing delays.

PerPageFax simplifies international and one-time faxing, offering secure online transmission with confirmation, as long as the destination number and return line are verified.

How Do I Know Which SS-4 Fax Number to Use?

The IRS doesn’t route your application based on where you happen to be standing when you send the fax. It routes based on the entity’s legal residence, principal place of business, or principal office or agency. That distinction trips up a surprising number of applicants, especially those using an online fax service from a different city or state than the business they’re registering.

If a Delaware LLC’s owner is faxing from a hotel in California, the number that matters is the entity’s principal place of business, not the sender’s location. Get this wrong and your fax may sit in the wrong queue.

Here are the three official Fax-TIN numbers and when each applies:

855-641-6935 — for entities with legal residence, principal place of business, or principal office in any of the 50 states or DC.
855-215-1627 — for entities with no U.S. state or DC residence, when faxing from inside the United States.
304-707-9471 — for entities with no U.S. state or DC residence, when faxing from outside the United States.

Pro Tip: IRS fax numbers can change without notice, so confirm the number on IRS.gov right before you send, not just when you first researched it. This single habit prevents more delays than any other step in the process. For a running reference, PerPageFax’s IRS fax number lookup tracks changes as they happen.

Should You Fax Form SS-4 or Apply Online Instead?

Faxing isn’t always the fastest route, but it’s often the only one available. The IRS’s online EIN application issues an EIN instantly, which beats waiting four business days for a fax. Online applications, though, only work under specific conditions.

Online filing requires a legal residence or principal place of business in the United States or a U.S. territory and a responsible party who holds a valid SSN, EIN, or ITIN.

Faxing becomes the right call when your entity operates outside the U.S., when the responsible party lacks a qualifying taxpayer ID, or when the online system simply won’t accept your entity type. Whichever method you choose, stick to one. Submitting the same application by fax, mail, and online in parallel is a common mistake that can generate duplicate EINs for a single entity, which then requires additional IRS correspondence to untangle.

Online versus fax EIN application comparison

What Should You Check Before Faxing Your SS-4?

A rejected or delayed SS-4 almost always comes down to something small. Run through this checklist before you send anything:

Download the current fillable Form SS-4 directly from IRS.gov rather than reusing an old saved copy. The IRS periodically revises the form, and outdated versions can cause processing delays.
Fill in the responsible party’s full legal name and taxpayer ID (SSN, ITIN, or EIN) exactly as it appears on their own tax records.
Complete the third-party designee section and get it signed if someone other than the responsible party is authorized to receive the EIN and answer IRS questions about the application.
Sign the form yourself where required. An unsigned SS-4 is one of the fastest ways to trigger a request for more information.
Enter a working return fax number and confirm that number can actually receive inbound faxes. This is where the EIN comes back to you.
Keep a copy of the completed form and the outbound transmission confirmation together in one place, ideally labeled with the date and destination fax number.

Pro Tip: Before you fax, call or test the return fax line once to make sure it’s live. A dead inbound line is the single most common reason applicants report never receiving their EIN by fax.

Missing or mismatched information, an unsigned form, or an inactive return fax number are the top reasons the IRS has to reach out for clarification, which adds days or weeks to a process that should take about four business days.

What’s the Best Way to Actually Send the Fax?

You have essentially three paths: a physical fax machine, a shared office fax line, or an online fax service. Each works, but the steps differ slightly.

Sending from a physical or office fax machine:

Create a simple cover sheet listing your business name, the responsible party’s name, and your return fax number.
Confirm the destination number matches your entity’s filing category.
Send the SS-4 along with the cover sheet as the first page.
Keep the printed transmission confirmation slip the machine generates.

Sending through an online fax service:

Export your completed SS-4 to a clean, fax-ready PDF.
Upload the PDF and enter the correct IRS Fax-TIN number as the destination.
Double-check the return fax number field, since that’s what the IRS will use to send your EIN back.
Choose secure, encrypted delivery with automatic retry if the line is busy.
Download and save the delivery receipt once transmission completes.

A few practical notes matter here too:

If you’re faxing from outside the U.S. for a foreign entity, use 304-707-9471 and account for international dialing formats and any long-distance charges your provider applies.
Label saved records clearly: entity name, date sent, destination number, and confirmation ID.
Store both the outbound confirmation and the completed SS-4 PDF somewhere you can retrieve quickly if the IRS follows up.

How Long Does It Take to Get an EIN Back by Fax?

Applications submitted through Fax-TIN generally come back with an assigned EIN within about four business days, assuming the form is complete and the return fax number is active. That four-day window is the benchmark the IRS itself sets, and it depends heavily on you doing your part correctly the first time.

If you don’t provide a working return fax number, the IRS shifts to mailing your EIN confirmation instead, which typically takes multiple weeks. That’s a real cost for something as simple as a missing or wrong digit in the return number field.

If four business days pass with no response:

Confirm you kept your outbound transmission receipt and a copy of the completed SS-4, since IRS staff will likely ask for both.
Contact the IRS Business & Specialty Tax Line rather than assuming the fax was lost.
Resist the urge to file a second SS-4 for the same entity. Submitting again while the first is still processing is exactly how duplicate EINs happen.

What Mistakes Cause SS-4 Faxes to Fail or Delay?

Most SS-4 fax problems trace back to a handful of repeat offenders, and nearly all of them are avoidable with a quick check before you hit send.

Wrong destination number. Applicants often fax based on where they’re physically located instead of the entity’s legal residence or principal place of business. Verify the entity’s actual filing category first, every time.
Dead return fax line. If the number you list can’t receive inbound faxes, your EIN has nowhere to go. Test the line or use a number you know accepts faxes reliably.
Missing signature or designee authorization. An unsigned form, or a designee section left incomplete, is a near-guaranteed trigger for IRS correspondence requesting more information.
Accidental duplicate filings. If you’re unsure whether a prior SS-4 for the same entity is still processing, don’t file again. Call the IRS Business & Specialty Tax Line first to check status and get guidance on resolving any duplicate EIN issue.

Pro Tip: Screenshot or save the confirmation page every time you send a fax through an online service. If the IRS asks for proof of transmission weeks later, that timestamped confirmation is what settles the question.

How PerPageFax Helps You Avoid Common SS-4 Fax Failures

Most SS-4 fax failures come down to two things: the wrong destination number, or a return fax line that never receives the EIN. The service addresses both directly. Transmissions include encryption, automatic retries if the line is busy, and a delivery confirmation you can keep alongside your completed form.

Before sending, you can use PerPageFax’s IRS fax number lookup to confirm you have the current destination number for your entity type, build a proper cover sheet with your return fax number listed correctly, and convert your completed SS-4 into a clean, fax-ready PDF. That combination, correct number, legible document, confirmed return line, is what actually determines whether your EIN comes back in four business days or gets stuck in follow-up correspondence.

What Actually Prevents SS-4 Fax Delays?

Most guides treat SS-4 faxing as a formality: fill in the form, pick a number, send it. The real failure points are almost always operational, not procedural. The IRS form itself is straightforward. What derails applicants is skipping the verification step on the fax number, or assuming a return line works without ever testing it.

A short habit checklist saves more time than any amount of re-reading the instructions: verify the destination number against the entity’s actual legal residence, test the return fax line before you rely on it, submit through exactly one method per entity, and save every confirmation you generate. None of that requires expertise. It requires discipline, and it’s the difference between an EIN in four days and one that takes a month because of a correspondence loop that started with a single missing digit.

— Engin

Send Your SS-4 Without Chasing Down a Fax Machine

PerPageFax gets your SS-4 to the IRS without requiring an account, a subscription, or access to an actual fax machine, just a completed PDF and $0.50 per page. That matters most for applicants who need to send one urgent form and don’t want to sign up for a service they’ll use once.

Start by exporting your completed Form SS-4 to PDF. If your document needs formatting adjustments before it will transmit cleanly, PerPageFax’s PDF faxify tool handles that in a few clicks. Upload the file, enter the correct IRS Fax-TIN number for your entity type, and list your return fax number carefully, that’s where your EIN comes back. Every transmission through PerPageFax includes encryption, automatic retries if the line is busy, and a delivery confirmation you can save with your records. If you’re sending internationally, PerPageFax supports fax delivery to 35 countries at the same flat per-page rate.

Once your cover sheet and PDF are ready, send your SS-4 through PerPageFax’s online fax service and keep the delivery receipt on file until your EIN arrives.

Send Your SS-4 Without Chasing Down a Fax Machine — overview diagram

This article is general information, not tax advice. Consult a qualified tax professional about your own circumstances before acting on anything here.

FAQ

Where Do I Fax My SS-4 Form?

Fax to 855-641-6935 if your entity’s legal residence or principal place of business is in one of the 50 states or DC. If there’s no U.S. state or DC residence, fax to 855-215-1627 from inside the U.S. or 304-707-9471 from outside the country.

How Do I Send My SS-4 to the IRS?

Complete the current fillable Form SS-4, sign it where required, list a working return fax number, and fax it to the Fax-TIN number matching your entity’s location. You can do this from a physical fax machine or an online fax service like PerPageFax, which lets you upload a PDF and send it for $0.50 per page.

Can I Get a Copy of My SS-4 Form Online?

Yes. The current fillable version of Form SS-4 is available directly on IRS.gov, and you should always use that current version rather than an older saved copy to avoid processing issues.

Can an SS-4 Be Filed Electronically?

The IRS offers an online EIN application for entities with a U.S. or territory-based principal place of business and a responsible party holding a valid SSN, EIN, or ITIN. Applicants who don’t meet those conditions, including many international entities, use fax or mail instead.