How to fax Form SS-4 to the IRS for an EIN: numbers and timing

Fax Form SS-4 to 855-641-6935 when the business is based in one of the 50 states or the District of Columbia, and write a fax number on the form: the IRS faxes the EIN back in about 4 business days, though its processing-status page lists faxed SS-4s at 8 business days. The IRS recommends applying online when possible.

How do you fax Form SS-4 to get an EIN?

Fax a completed Form SS-4 with a fax number on it to the IRS Fax-TIN number for the applicant's location, and the IRS faxes the EIN back to that number.

1. Download the fillable Form SS-4 from IRS.gov and complete it.
2. Write the applicant's fax number, with area code, on its line, and the designee's fax number when a designee applies.
3. Complete the signature area, which a designee's authorization needs to be valid.
4. Fax the form to 855-641-6935 from the 50 states or the District of Columbia, or to the number for an applicant without a base in a state.
5. Keep the record that shows the fax went through, then watch the return line for the IRS cover sheet with the EIN.

The Form SS-4 instructions give the ways to apply: online for applicants in the United States or U.S. territories only, by telephone for applicants outside them only, by fax, or by mail, depending on how soon the EIN is needed. The IRS recommends applying online when possible, and its EIN page says an EIN is free directly from the IRS and comes online in minutes.

Which IRS fax number do you use?

The IRS fax number for Form SS-4 is 855-641-6935 when the applicant's legal residence, principal place of business or principal office is in one of the 50 states or the District of Columbia, and 855-215-1627 from inside the United States or 304-707-9471 from outside it when there is no such base. Each IRS fax route, its number and the processing time the IRS states sit in the table below, with the authorization forms beside them.

Fax-TIN numbers can only be used to apply for an EIN, may change without notice, and take faxes 24 hours a day, 7 days a week.

How long does a faxed SS-4 take, and how does the EIN come back?

A faxed SS-4 brings the EIN back by fax in about 4 business days when the form gives a fax number, the IRS's EIN page says, while the IRS processing-status page lists faxed SS-4s as processed 8 business days after receipt.

The Form SS-4 instructions say that under the Fax-TIN program an applicant can receive the EIN by fax generally within 4 business days. The EIN page says the IRS faxes back a cover sheet with the EIN and no longer returns the Form SS-4 notated with the EIN. The processing-status page, last reviewed October 16, 2026, lists faxed SS-4s at 8 business days after receipt and paper applications within 30 days of receipt.

The EIN comes back to the fax number on the form, and the instructions tell applicants to be sure to provide one. That return number must be able to receive faxes, the job of a dedicated fax number. If a return is due before the EIN arrives, the instructions say to write "Applied For" and the date of the application in the space for the number.

What has to be on the form before you fax it?

Form SS-4 needs the applicant's fax number, with area code, on its line before it is faxed, plus the designee's fax number and a completed signature area when a third-party designee applies.

The fillable Form SS-4 downloaded from IRS.gov is suitable for faxing or mailing once completed, and the form itself carries both fax lines. The IRS allows only one EIN application per day, whether online, by phone, by mail or by fax. The instructions say to use only one method for each entity, so the entity does not end up with more than one EIN.

Can an accountant or another designee fax it for you?

An accountant or another third-party designee named on Form SS-4 can apply for the EIN, and the IRS releases the EIN to the designee by the method used to apply while mailing the EIN notice to the taxpayer.

The designee's authorization is valid only when the signature area is completed. If the designee's address or telephone number matches the taxpayer's, the application must be mailed or faxed. An application the designee faxes brings the EIN back to the designee by fax, on the designee's fax line from the form.

When does a practice need a new EIN, and what do payers ask for?

A practice generally needs a new EIN when its ownership or structure changes, and it keeps its EIN through a change of name, address or responsible party. After an organizational change, payers such as Blue Cross and Blue Shield of Texas and of Illinois ask for an updated W-9 with official IRS documentation, which the Texas plan illustrates as an SS-4 or 147c.

Form 8822-B reports a change of responsible party, address or location, and a change of responsible party must be reported to the IRS within 60 days. To confirm an EIN already issued, a business calls the IRS business and specialty tax line and asks for Letter 147C, EIN Previously Assigned.

Aetna says the TIN owner name on the W-9 is the legal name used on line 1 of the Form SS-4 sent to the IRS. Blue Cross and Blue Shield of Texas asks an in-network provider or group with an organizational change for a new provider onboarding application with an updated W-9 and official IRS documentation such as an SS-4 or 147c.

Blue Cross and Blue Shield of Illinois has new providers submit a W-9 with both the legal name and any Doing Business As name, starting August 1, 2026. Its current in-network providers need a new W-9 only after an organizational change such as a name or TIN change, sent with official IRS documentation in a new provider onboarding application. The IRS's Form W-9 says a new W-9 is due when the name or TIN changes, and the form goes to the requester, never to the IRS.

How do Forms 2848 and 8821 go by fax?

Forms 2848 and 8821 go by fax to the IRS number for the filer's state, 855-214-7519 in Memphis or 855-214-7522 in Ogden, with a handwritten signature.

Memphis takes filers in Alabama, Arkansas, Connecticut, Delaware, the District of Columbia, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia and West Virginia. Ogden takes Alaska, Arizona, California, Colorado, Hawaii, Idaho, Iowa, Kansas, Minnesota, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, Wisconsin and Wyoming. A Form 8821 filer outside the 50 states and the District of Columbia faxes the International CAF Team at 855-772-3156, or 304-707-9785 from outside the United States.

The Form 2848 instructions require a handwritten signature on a form filed by fax or mail, and digital, electronic or typed signatures count only on a form submitted online; the Form 8821 instructions set the same handwritten rule for fax and mail. The processing-status page lists both forms at 3 business days after receipt and asks filers not to send a duplicate. For faster processing of certain authorizations, the IRS points to the all-digital Tax Pro Account, where most requests record immediately to the Centralized Authorization File.

The other IRS forms a tax office sends by fax are covered in secure fax for accountants and tax preparers.

How do you send and receive IRS faxes from a HIPAA fax account?

On a paid Fax Pigeon plan, the practice's own number receives the IRS's fax with the EIN. A PDF or a phone photo of the signed form uploads as it is. Every delivered fax gets delivery proof. The shared inbox shows the EIN to whoever handles payer paperwork.

* Official sources (the IRS, Aetna, Blue Cross and Blue Shield of Texas, Blue Cross and Blue Shield of Illinois) were read on October 20, 2026. Fax Pigeon prices and plan terms as of October 20, 2026.