# How to fax Form SS-4 for an EIN

Choose the correct IRS route, prepare a signed SS-4, and include a working return fax number for your EIN application.

Published: 2026-10-04

Canonical: https://dearfax.com/guides/how-to-fax-ss4-for-ein

Form SS-4 is an application for an employer identification number. First check whether you already have an EIN and whether the IRS online application fits your circumstances. A missing confirmation letter is not a reason to apply for another EIN; see the [147C receiving guide](https://dearfax.com/guides/how-to-receive-irs-147c-letter).

## Choose the correct fax destination

Use the [SS-4 fax number finder](https://dearfax.com/irs-fax-numbers/ss-4). The IRS distinguishes the location of the principal business, office or agency, or an individual’s legal residence. For the international route, it also distinguishes whether you are faxing from within or outside the US.

A US incorporation address alone does not establish which route applies. Check your circumstances against the [IRS where-to-file instructions](https://www.irs.gov/filing/where-to-file-your-taxes-for-form-ss-4). Do not send the same application to multiple destinations to increase the chance of a reply.

## Complete and sign the current form

Download Form SS-4 and read the [IRS instructions](https://www.irs.gov/instructions/iss4). Check the legal name, address, responsible party, entity type and reason for applying. Resolve uncertainty before submitting rather than letting an assistant guess at tax information.

Make sure the required signature is present and every page is legible. Keep the submitted version so you can refer to the same details if you need to follow up.

## Set up a return fax number

The IRS fax process uses a return fax number when supplied. Use an active number you control and can monitor. DearFax’s Free sending allowance does not include a dedicated receiving number; receiving requires Pro or Business and an active number.

Include the return number in the application as instructed. A callback telephone number and a receiving fax number serve different purposes.

## Review and send

Prepare the PDF, select the route from the finder, and review the destination, signature and page count before authorizing sending. In [ChatGPT](https://dearfax.com/chatgpt) or [Codex](https://dearfax.com/codex), you can use DearFax’s [MCP connection](https://dearfax.com/mcp) to prepare a fax and review it before confirming. Provide the verified destination yourself and keep the tax details under your control.

Save the delivery result. Successful transmission is not confirmation that the IRS has accepted the application or assigned an EIN.

## Monitor the reply and follow up

Check your receiving inbox and the IRS’s [current processing status](https://www.irs.gov/help/processing-status-for-tax-forms). Published timeframes are estimates. If you need to follow up, use the IRS’s current EIN contact instructions and have your submitted form and transmission record ready.

Avoid an automatic resend schedule. First establish whether the original application is pending and follow the IRS’s direction about resubmitting.

## Common questions

### Should I use SS-4 to replace a lost EIN letter?

No. Request confirmation of the existing EIN through the IRS verification process. The [147C guide](https://dearfax.com/guides/how-to-receive-irs-147c-letter) explains how to prepare for receiving it.

### Can I send from outside the United States?

The IRS publishes an international fax route. Use the finder to distinguish your business location and where you are sending from, and confirm that your fax service supports the destination.