An EIN is the first thing a new US company needs: to open a bank account, sign up for Stripe, hire, or file anything with the IRS. Most people get one online in ten minutes. But a large group can’t use the online application, especially foreign founders of US LLCs and corporations, and for them the choice is mail (about 4 weeks) or fax (about 4 business days).
The IRS calls the fax route Fax-TIN. Here’s everything you need to use it: the numbers, the form details that cause rejections, and the step almost everyone misses, which is having a way to receive the EIN when the IRS faxes it back.
Checked against the Instructions for Form SS-4 (Rev. 12-2025) and the IRS’s internal EIN procedures (IRM 21.7.13, updated October 1, 2026), on October 17, 2026.
Form SS-4 fax numbers
| If the business… | Fax Form SS-4 to |
|---|---|
| Has a legal residence, principal place of business, or principal office in one of the 50 states or DC | 855-641-6935 |
| Has none of those in any state or DC (US territory or international), and you’re faxing from within the US | 855-215-1627 |
| Same, and you’re faxing from outside the US | 304-707-9471 |
The Fax-TIN lines run 24 hours a day, 7 days a week, and accept only EIN applications. Other forms sent there won’t be processed. For every other IRS fax number, see our IRS fax numbers guide.
Fax, online, phone, or mail: which should you use?
| Your situation | Best method | How fast |
|---|---|---|
| Business in the US/territories, and the responsible party has an SSN, ITIN, or EIN | Online at IRS.gov/EIN | Immediately |
| Foreign owner with no SSN or ITIN | Fax | ~4 business days |
| Foreign owner who wants it today and can call during US hours | Phone: 267-941-1099 (not toll-free), 6 a.m.–11 p.m. Eastern, Mon–Fri | During the call |
| No access to fax or phone | ~4 weeks |
Phone is only available to international applicants. The IRS no longer issues EINs by phone to domestic applicants. For anyone who can’t apply online, fax is the dependable middle ground: no waiting on hold across time zones, and a paper trail of exactly what you submitted.
The step most people miss: a fax number to receive the EIN
Here’s how the fax route actually works. You fax the SS-4. An IRS examiner processes it. Then the IRS faxes a cover sheet with your EIN back to the fax number you wrote on the form, in about 4 business days.
If you leave the “Applicant’s fax number” box empty, you don’t get the fast version: the IRS mails a confirmation letter to your address instead, which takes about two weeks (longer if you’re overseas). And if the IRS’s fax-back fails, it retries once, then switches to mail. A home fax machine that’s out of paper, or a shared office line that’s busy, can cost you weeks.
So you need a fax number that’s always on. Your options:
- An online fax number. A Browserfax plan gives you a dedicated US fax number the moment you subscribe, for $8/month. It answers 24/7, receiving is unlimited, and the IRS’s fax lands in your inbox and email wherever you are in the world. Put the number in the “Applicant’s fax number” box. Once your EIN arrives, you can keep the number for future IRS letters or cancel online. (How to get a fax number · Fax to email)
- Your formation agent’s or accountant’s fax, if you name them as third-party designee (see the signature rules below).
- A fax number you already have.
Keep the number active until the EIN arrives. If your application is missing information, the IRS faxes the problem notice to the same number.
Filling out Form SS-4 so it isn’t rejected
The form is a single page (current revision: December 2025). Most delays come from a handful of lines:
- Line 4a–4b (mailing address) must be the business’s own address, not your formation agent’s. The IRS will reject an application where the mailing address is the third-party designee’s. A designee can receive the EIN, but not your mail.
- Lines 7a–7b (responsible party) must name an individual, a real person, not a company. If the responsible party doesn’t have and isn’t eligible for an SSN or ITIN, write “foreign” or “N/A” on line 7b. An entry is required, and a blank line 7b stops the application.
- Line 9a (entity type) for a foreign-owned single-member LLC: check Other and write “Foreign-owned U.S. disregarded entity-Form 5472”, the exact wording the instructions give for an LLC wholly owned by a foreign person.
- Line 10 (reason for applying): check exactly one box. “N/A” isn’t accepted there. On other lines that don’t apply, do write “N/A” rather than leaving them blank.
- Fill in “Applicant’s fax number” (or the designee’s fax number), or there’s nothing for the EIN to be faxed back to.
- If you name a third-party designee, sign by hand. The IRS has waived the general signature requirement for Form SS-4, but authorizing a designee is the exception: it needs a handwritten signature, date, and title. With an electronic signature, the IRS still assigns the EIN but won’t release it to the designee.
- One application per responsible party per day. The IRS issues one EIN per responsible party per day, whatever the method.
How to fax Form SS-4 from anywhere, without a fax machine
- Complete the form and save it as a PDF. If you’re naming a designee, print it, sign by hand, and scan or photograph it.
- Open browserfax.com/app in any browser, in any country. There’s nothing to install.
- Enter the right SS-4 number from the table above. The picker defaults to the US, which is correct for all three numbers.
- Upload the PDF and check the page count. The form itself is one page.
- Click Send and sign in with Google. You get 20 free pages with no credit card, and the IRS numbers are US numbers, so your SS-4 costs nothing to send, even from abroad.
- Watch the status go Queued → Sending → Delivered, and keep the confirmation email as your record of when you applied.
Timing tip: faxes that reach the EIN unit after 1 PM Eastern count as received the next business day. That’s 6 PM in the UK and 7 PM in Central Europe, so send earlier in your day to save one.
If the line is busy, the fax shows Failed and the page goes back to your balance automatically. Just resend.
After you fax
- Day 1–4 (business days): the IRS processes the application. Faxed applications have a 4-business-day processing target.
- Fax-back: a cover sheet with your EIN arrives at your return fax number. On Browserfax it appears in your inbox and you get an email.
- Nothing after the 4th business day? Call 800-829-4933 for verbal confirmation of the EIN, or 267-941-1099 from outside the US.
- Got a problem notice instead? The IRS faxes a cover sheet explaining what’s missing. Fix it and fax the corrected form back to the same number.
- Don’t apply twice. The IRS asks you to use only one method per entity so you don’t end up with two EINs. Wait for the fax-back, or call, before resending.
What usually comes next
Once you have the EIN, the next IRS filing for many small businesses is the S corporation election (Form 2553), which has a strict 2-month-15-day deadline and is also faxable. See How to Fax Form 2553. If you hire someone to deal with the IRS for you, Forms 2848 and 8821 are faxable too (IRS fax numbers).
The bottom line
If you can apply online, do that. If you can’t, which is the case for most foreign founders, fax is the fastest reliable route: about 4 business days, with no hold music. Use the right number for your situation, write “foreign” on line 7b if you have no SSN or ITIN, sign by hand if you name a designee, and above all give the IRS a fax number that will actually pick up. Sending the SS-4 on Browserfax is free, and a US number to receive the EIN is $8/month with unlimited receiving.
Verified October 17, 2026 against Instructions for Form SS-4 (Rev. 12-2025), Form SS-4 (Rev. 12-2025), and IRM 21.7.13, Assigning Employer Identification Numbers (fax-back timeline, 1 PM Eastern cutoff, failed fax-back retry, third-party designee signatures). The IRS can change these numbers without notice, so confirm on the linked page before sending. This article is general information, not tax or legal advice.