The IRS does not have one fax number. It has a different one for each form, region, and notice, and the wrong one is how a response disappears. The directory below covers the destinations people ask about most. One rule applies to every row: if the IRS sent you a notice, the number on that notice wins. A regional number in a directory is a fallback. It does not replace the number printed on your letter by the agent on your case.
IRS Fax Number Directory
| What you’re faxing | Fax number | Notes |
|---|---|---|
| Form SS-4 (EIN application, domestic) | (855) 641-6935 | 50 states + DC. The IRS faxes your EIN back in about 4 business days. Full walkthrough: How to fax Form SS-4 for an EIN. |
| Form SS-4 (EIN, international applicants) | (855) 215-1627 (from inside the U.S.) or +1 (304) 707-9471 (from outside the U.S.) | For applicants whose main business address is outside the United States. |
| CP2000 audit / notice response | Printed on the top-left of your specific notice | The IRS publishes seven regional CP2000 fax numbers (Andover, Atlanta, Austin, Holtsville, Fresno, Ogden, Philadelphia), but the only correct one is the one on your CP2000 letter. |
| Form 2848 (Power of Attorney) | (855) 214-7519 Memphis (Eastern states) · (855) 214-7522 Ogden (Western states) · (855) 772-3156 or (304) 707-9785 International CAF | Routed by the taxpayer’s state of residence. Full state list is in the Form 2848 instructions. |
| Form 8821 (Tax Information Authorization) | Same as Form 2848: (855) 214-7519 Memphis · (855) 214-7522 Ogden · (855) 772-3156 / (304) 707-9785 International | Form 8821 routes through the same CAF units as Form 2848. |
| Form 1310 (refund due a deceased taxpayer) | No general fax number | Form 1310 is normally filed with the deceased taxpayer’s return by mail or e-file. Only fax it if an IRS agent or notice requests it, and use the number they give you. |
| Form 433-D (installment agreement) | No general fax number | This is signed and returned to the revenue officer or ACS agent working your case. Use the fax number on the letter or in the agent’s instructions. |
| General audit response / IRS audit fax number | Printed on the agent’s letter | If an examiner asks for documents, the fax number is in their correspondence. The IRS does not run one "audit fax" line you can look up. |
The pattern is hard to miss: applications (SS-4, 2848, 8821) have stable, publicly listed numbers. Anything tied to a specific case file or notice does not. That is not a quirk of the table – it is how the IRS is organized. Using the wrong number does not "forward" anywhere either. It usually means starting over.
CAF, in case you were wondering, stands for Central Authorization File – the IRS unit that processes power-of-attorney and authorization filings.
Always verify against your specific notice
Fax numbers in this directory are accurate as of publishing, and the IRS notes in its form instructions that they "may change without notice." Before you send anything time-sensitive:
- Use the fax number on your IRS notice or your agent’s letter first.
- If you’re faxing an application without a notice (like Form SS-4 or Form 2848), confirm the current number at IRS.gov under the page for your specific form.
- Keep a printed or PDF copy of the page that lists the number you used, in case the IRS later disputes where you sent your response.
- If you’ve lost your notice, call the IRS or your tax professional for another copy. Do not guess at an unverified number.
You Cannot Fax Your 1040
This part hasn’t changed, and it’s the question we get most often: you cannot fax your annual Form 1040 to the IRS. There is no fax number for annual income tax returns.
Annual returns go through one of two channels:
- E-file (used for 97% of individual returns in recent IRS filing seasons), which gives you a same-day accepted-or-rejected receipt.
- Paper mail to the address listed in the Form 1040 instructions for your state.
Faxing is reserved for narrower situations: responding to an IRS notice, sending documents an examiner has specifically asked for, or filing certain applications like Form SS-4 that have their own fax channel. Sending your 1040 by fax when nobody asked for it is not a faster route, it’s a discarded one.
Preparing Your Fax to the IRS
Once you have the right number, the fax to the IRS itself is the easy part. The IRS rejects more responses for sloppy packaging than for the wrong destination. A quick checklist:
- Cover sheet with your full legal name, SSN/ITIN/EIN, the tax year, the exact notice number you’re responding to (e.g. "Response to Notice CP2000"), a return phone number, and the total page count. Our free printable fax cover sheet is laid out for this use case.
- Scan at 300 DPI or higher and combine your cover sheet plus all supporting documents into one PDF. The IRS receives the fax as a black-and-white image. Anything fuzzy on your end will be unreadable on theirs – and unreadable numbers are the most common cause of "we need more information" follow-ups.
- Cover sheet first, response second, supporting documents in the order they’re referenced. Skip duplicate pages; the IRS often photocopies what arrives, and duplicates just multiply the photocopying.
Sending and Keeping Proof
The IRS does not send a "received" acknowledgment, by mail or any other channel. That means a transmission confirmation report is the only proof you ever get that your fax landed. If a follow-up notice ever claims you didn’t respond, the confirmation report is the document that ends the argument. Keep it with the rest of that year’s tax records for at least three years, which is the standard IRS audit window.
A modern online fax service handles two things a physical fax machine doesn’t: encryption in transit, and a permanent transmission report you can store with your tax records. Through PayPerFax, you upload your prepared PDF, enter the IRS fax number from your notice, and pay per page. When the fax completes, you get a confirmation report showing the destination number, page count, date, time, and successful delivery.
If you’re wondering about send time, how long an online fax takes covers it – most IRS faxes complete in a few minutes, and the confirmation arrives immediately after.
Frequently Asked Questions
Can I fax my Form 1040 to the IRS?
No. The IRS does not accept annual Form 1040 returns by fax. Use e-file or paper mail to the address in the Form 1040 instructions. Fax is for specific notices, examinations, and applications like Form SS-4.
Is there one IRS fax number for everything?
No. The IRS routes faxes by form and by region. Form SS-4 has its own numbers, Forms 2848 and 8821 share the CAF unit numbers, and CP2000 responses go to the regional office printed on the notice. Using the wrong number does not "forward" anywhere – it usually means starting over.
What if the fax number on my notice and the number on IRS.gov disagree?
Use the one on your notice. The number on the notice is tied to the agent or office handling your specific case. The number on IRS.gov is a general number that may not match where your file is being handled.
How do I know the IRS received my fax?
The transmission confirmation report from your fax service. The IRS does not send a "received" notice, by mail or otherwise. Save the confirmation report with your tax records.
What happens if my fax to the IRS fails?
Re-check the fax number for typos first, since one wrong digit accounts for most failures. If the number is correct, the IRS line is sometimes congested – wait an hour and resend. If a hard deadline is looming and the line keeps failing, mail your response by USPS Certified Mail. Document the failed fax attempts in your records.
Is faxing tax documents secure?
Online fax services like PayPerFax encrypt your document in transit and store the transmission record under your account. That is meaningfully more private than a shared office or copy-shop fax machine where the document can sit on a tray.
Ready to fax to the IRS with a permanent, verifiable record? Send your fax now with pay per fax – no subscriptions, no failed-fax charges, and a confirmation report the moment your fax goes through.