You can fax Form SS-4 to the IRS to apply for an EIN, and it is often faster than mail. The key steps are confirming the current fax number on irs.gov, completing the form cleanly, and sending it with a cover sheet. If you do not own a fax machine, Faxend, our own iOS app, is the fastest way to send it from a phone.
What Form SS-4 Is and Why You Would Fax It
Form SS-4 is the application for an Employer Identification Number, the tax ID your business uses to open bank accounts, hire employees, and file returns. You can apply online, by mail, or by fax, and fax often sits in the sweet spot. It is faster than mail, and it works in cases where the online tool will not, such as when the responsible party already holds an EIN or the entity has a foreign owner.
Faxing also leaves a clean paper trail. When I fax an SS-4, I keep the transmission confirmation so I can prove the exact date I sent it. That receipt is useful weeks later if you need to follow up on your EIN.
This guide walks through finding the right number, sending the form with or without a machine, and knowing when to expect a reply. For more background, browse our other how-to fax guides.
Find the Correct IRS Fax Number Before You Send
The IRS routes SS-4 faxes to different units depending on where your business is located and whether you have a US address. Those numbers change over time, so I never trust a number pulled from an old article or a forum thread.
Open the official Form SS-4 page on irs.gov and read the current instructions, then find the Where to File or Fax section. Match your state, or your foreign status, to the number listed there. If the IRS page shows something different from what you expected, trust the IRS page.
Domestic and international applicants use different fax numbers. Confirm which one applies to you on irs.gov before sending, because a fax delivered to the wrong unit can be discarded rather than forwarded.
If you want a fuller walkthrough of locating the right line, see our guide to IRS fax numbers.
How to Fax Form SS-4 Without a Fax Machine
Most people applying for an EIN do not own a fax machine, and you do not need one. Our top pick is Faxend, the fastest way to send a fax from an iPhone. Faxend, our own iOS app, is free to download and turns a photo or PDF of your completed SS-4 into a fax in a couple of taps. Per fax or plan pricing applies.
- 1Fill out and save your SS-4 as a PDF.Complete every required line, then export or scan it into a single clean PDF.
- 2Enter the IRS fax number.Use the number you just confirmed on irs.gov, not one from memory.
- 3Attach the form and a cover sheet.Include your name, callback number, and total page count so the IRS can match your fax.
- 4Send and save the confirmation.Keep the delivery receipt with your records in case you need to prove the send date.
The same approach works from a computer with a web fax service, though an app is quicker for a single filing.
Faxend is our top pick for sending a fax from an iPhone. It is the app we build, it is free to download, and it turns a photo or PDF into a fax in a couple of taps. Per-fax or plan pricing applies.
What to Include on the Fax and Cover Sheet
Before you send, check that the responsible party name, address, and signature match your other filings. Mismatched names are one of the most common reasons an SS-4 gets kicked back.
A short cover sheet helps the IRS process your application. Include your business name, the responsible party name, a callback phone number, a return fax number, and the total page count. If you want the EIN faxed back to you rather than mailed, state that return fax number clearly at the top.
Our overview of what the IRS accepts by fax explains why a legible, single-purpose fax gets processed faster than a bundle of mixed documents.
How Long Until the IRS Sends Your EIN Back
When you fax SS-4 with a valid return fax number, the IRS typically responds in about four business days, though the exact timing shifts with their workload. Without a return fax number, the reply comes by mail and can take several weeks.
If you have not heard back, resist the urge to refax right away. Sending a duplicate can create two applications and slow everything down. Wait out the stated window, then call the IRS Business and Specialty Tax Line to check on your EIN status.
Keeping your transmission confirmation is what makes that follow-up call easy, since you can state the exact date and time you sent the form.
Ways to Fax Form SS-4 to the IRS, Compared
Here is how the common methods stack up. I ranked them by how quickly most people can actually get a fax out the door.
| Method | Best for | Typical cost | Notes |
|---|---|---|---|
| Faxend | iPhone users sending a one off SS-4 | Free to download, per fax or plan | Our top pick. Photo or PDF to fax in a couple of taps |
| Web fax service | Desktop users who fax often | Around $8 to $13/mo as of writing | Good for volume, usually needs a subscription |
| Free fax website | A single low page count fax | Free with limits | Ads, watermarks, and page caps are common |
| Physical fax machine | Offices that already own one | Hardware plus a phone line | Slowest to set up if you do not have one |
| In store fax counter | People near a print shop | A few dollars per page | Privacy is limited at a shared counter |
For the desktop route, our guide to faxing the IRS without a fax machine covers browser based options in more detail.
Common SS-4 Faxing Mistakes to Avoid
A few small errors cause most rejected or delayed SS-4 faxes. Watch for these before you hit send.
- Using an outdated fax number instead of the current one on irs.gov.
- Leaving off a return fax number when you want the EIN faxed back.
- Sending a blurry photo of the form instead of a clean, high contrast scan.
- Faxing the same SS-4 twice while waiting, which can create duplicate applications.
- Forgetting to sign, or signing with a name that does not match your other records.
Fix these up front and your application should move through without a second attempt.
Frequently asked questions
Yes. Faxing is one of the accepted ways to apply for an Employer Identification Number. You complete Form SS-4, confirm the correct fax number on irs.gov, and send it with a cover sheet. With a valid return fax number, the IRS usually faxes your EIN back within a few business days.
With a return fax number on your application, the IRS typically responds in about four business days, though timing varies with their workload. Without a return fax number, the EIN is mailed instead and can take several weeks to arrive.
The number depends on your location and whether you have a US address, and the IRS updates it periodically. Always confirm the current fax number on the official Form SS-4 page at irs.gov rather than reusing one from an old article or forum post.
Our top pick is Faxend, the fastest way to send a fax from an iPhone. It is free to download and turns a photo or PDF of your SS-4 into a fax in a couple of taps, with per fax or plan pricing at send time.
A cover sheet is not always strictly required, but it is strongly recommended. Include your business name, responsible party, callback number, return fax number, and page count so the IRS can match and route your SS-4 correctly.
