Where to Fax Form SS-4 (IRS EIN Application)
Faxing Form SS-4 gets you an EIN in about four business days when the online tool isn’t an option. Confirm the correct number below and send your application.
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Fax numbers and addresses were last verified July 17, 2026. The IRS can change them at any time — always confirm against the official source: IRS.gov — Instructions for Form SS-4.
Find your Form SS-4 fax number
The fax number depends on whether the business has a legal residence or principal place of business inside one of the 50 states or DC.
All Form SS-4 fax numbers and mailing addresses
Every destination is listed below so you can confirm yours directly.
Domestic applicants (any of the 50 states or DC)
Fax number
(855) 641-6935
Mailing address (alternative)
Internal Revenue ServiceAttn: EIN OperationCincinnati, OH 45999If you include your own return fax number, the IRS faxes your EIN back in about 4 business days. Mailing instead takes roughly 4 weeks.
States served: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming.
No legal residence or principal place of business in any state
Fax number (from within the US)
(855) 215-1627
From outside the US: (304) 707-9471
Phone option: (267) 941-1099
Mailing address (alternative)
Internal Revenue ServiceAttn: EIN International OperationCincinnati, OH 45999International applicants can fax 855-215-1627 from within the US, or 304-707-9471 from outside the US. The IRS also offers a phone option at 267-941-1099 for international applicants.
What Form SS-4 is and who needs it
Form SS-4, "Application for Employer Identification Number," is how you request an EIN — the nine-digit federal tax ID (format XX-XXXXXXX) that identifies a business entity to the IRS. You generally need an EIN if you have employees, operate as a corporation or partnership, file employment or excise tax returns, withhold taxes on income paid to a non-resident alien, or administer certain trusts, estates, or retirement plans. Banks also almost always require an EIN to open a business account.
A single responsible party — the individual who ultimately owns or controls the entity — must be named on the form, along with their SSN, ITIN, or (for entities) EIN. The IRS issues only one EIN per responsible party per day, regardless of the method you use.
Fax vs. the free online EIN tool
The IRS recommends its free online EIN Assistant for most domestic applicants, because it issues the EIN immediately at the end of the session. Faxing Form SS-4 makes the most sense when the online tool can’t be used: for example, when the responsible party is a foreign person without an SSN or ITIN, when a third-party designee is applying, when the entity hits one of the online tool’s eligibility limitations, or simply when you need to apply outside the online tool’s operating hours.
When you fax Form SS-4 and include your own return fax number, the IRS assigns the EIN and faxes it back to you — typically within about four business days. If you mail the form instead, expect roughly four weeks. That speed difference is the main reason people fax SS-4 rather than mail it.
Domestic vs. international routing
There is no state-by-state split for SS-4 the way there is for Form 2553 or Form 2848. Instead, the IRS uses a single domestic fax number — 855-641-6935 — for every applicant whose legal residence, principal place of business, or principal office is located in one of the 50 states or the District of Columbia.
If the entity has no legal residence or principal place of business in any state (for example, a foreign-owned business), it is handled by the IRS international operation: fax 855-215-1627 from inside the US or 304-707-9471 from abroad, or call 267-941-1099. Choose the international routing only when the domestic test genuinely doesn’t apply.
What to include when you fax Form SS-4
- A cover sheet listing your entity name, the responsible party, a callback number, and the page count.
- A complete, signed Form SS-4 — every required line, including line 7a/7b (responsible party and their SSN/ITIN/EIN) and the reason for applying on line 9a–10.
- Your own return fax number clearly on the form or cover sheet so the IRS can fax the EIN back.
- A Form 8821 or 2848, or line-18 third-party-designee section, if someone other than the responsible party should receive the EIN.
Common mistakes that get Form SS-4 rejected
- Leaving off your return fax number — without it the IRS mails the EIN, which takes weeks longer.
- An incomplete or missing responsible-party SSN/ITIN/EIN on line 7b.
- Applying more than once for the same entity (this can create duplicate EINs and processing headaches).
- Using the international fax number when the business actually has a US principal place of business (or vice versa).
- An unsigned form — SS-4 must be signed by the responsible party or an authorized designee.
After you fax Form SS-4
- Keep the fax transmission confirmation as proof of when you applied.
- Watch your return fax line: for domestic applications with a return fax number, the EIN typically comes back in about 4 business days.
- Once you receive the EIN, store the CP575 confirmation (or the faxed EIN letter) permanently — you’ll need it for banking, payroll, and future filings such as Form 2553.
- Do not re-apply while you’re waiting; duplicate applications can generate a second EIN you’ll then have to reconcile.
Form SS-4 fax FAQ
Related IRS forms
Last verified July 17, 2026. Official source: IRS.gov — Instructions for Form SS-4