How Does the IRS EIN Assistant Work?
The irs.gov EIN Assistant is an interactive Form SS-4. It runs weekdays, 7 a.m. to 10 p.m. Eastern, times out after 15 minutes of inactivity, issues 1 EIN per responsible party per day, and delivers the number at the end of the session.
| Rule | Detail |
|---|---|
| Hours | Monday to Friday, 7 a.m. to 10 p.m. Eastern |
| Session timeout | 15 minutes of inactivity ends the session |
| Daily limit | 1 EIN per responsible party per day |
| Who can use it | Applicants with an SSN or ITIN |
| Result | 9-digit EIN issued on screen, CP-575 by mail |
| IRS fee | $0 |
Source: IRS EIN Assistant and Form SS-4 instructions, verified August 2026.
The tool must be completed in 1 sitting, because it saves no progress. It walks the same 18 lines as the paper Form SS-4, then validates the responsible party before assigning the number. The full walkthrough is on apply for an EIN online for an LLC and the paper form on IRS EIN application form.
The session opens by asking for the entity type, then the reason for applying, then the responsible party and their SSN or ITIN. The IRS defines the responsible party as the 1 person who controls the entity and its funds, and the online tool checks that name against IRS records before it releases the number. When the check fails, the session ends with a reference number rather than an EIN: reference 101 flags a name conflict with an existing entity, and reference 102 flags a mismatch between the responsible party name and their SSN. Both stop the online route and push the applicant to the fax path on Form SS-4.
Because the assistant issues 1 EIN per responsible party per day, a founder forming several entities clears them across separate days rather than in 1 sitting. The step-by-step order of the screens is mapped on how to get an EIN and the online-specific walkthrough on apply for an EIN online.
No SSN. No passport upload.
What Does the IRS Charge for an EIN?
$0. The IRS has never charged for an EIN, by any method. A website that requires a mandatory fee to obtain the number is a third-party filer, not the IRS, and the IRS fee behind it is still $0.
This is the single fact that protects applicants from overpaying. Anyone holding an SSN completes the free irs.gov tool in 15 minutes and pays nothing. A paid service earns its fee only in the 1 case the free tool cannot serve: an applicant with no SSN and no ITIN, who must file by fax. The full price map, including the reference prices of other services, sits on LLC EIN cost and free EIN number for an LLC.
The $0 figure holds across all 4 IRS methods: the online assistant, fax on Form SS-4, mail, and the phone line for international filers. No method carries a surcharge, an expedite fee, or a processing charge from the IRS itself. A third-party filer instead charges for the work of preparing and faxing the SS-4 on the applicant's behalf, which is the service worth paying for when the free irs.gov tool rejects an applicant who holds no SSN and no ITIN. Our own filing runs $97 for the standard 7-business-day file and $127 for the 24-hour file, and the IRS fee inside both is still $0.
The practical test is simple: an applicant with an SSN who wants the number today opens the free tool and pays nothing, following apply for an EIN online. An applicant without one weighs the fax route, walked through on how to get an EIN.
What If You Cannot Use the irs.gov Tool Without an SSN?
File Form SS-4 by fax. The IRS accepts the word Foreign on line 7b, so it issues an EIN with no SSN and no ITIN. Fax to 855-641-6935 within the US or 855-215-1627 from abroad.
The online assistant is the only IRS route that requires an SSN, and it fails at the validation screen for applicants who hold neither an SSN nor an ITIN. The fax route has no such check, which is why founders across 150+ countries obtain a US EIN this way. The return fax carries the assigned 9-digit number, often weeks before the printed CP-575 reaches an address abroad. The route is detailed on LLC EIN without SSN and EIN for a foreign-owned LLC.
On the paper form, line 7a asks for the responsible party name and line 7b asks for that person's SSN, ITIN, or EIN. A non-US founder who holds none of those 3 writes the word Foreign in the 7b field, and the IRS accepts the form as filed. This is the exact mechanism that lets a single-member LLC owned by a non-resident obtain a US EIN with no US tax ID of any kind. The IRS does not require an ITIN first, and it does not require the owner to travel to the United States.
Fax is the fastest of the no-SSN routes. The IRS returns the assigned 9-digit EIN by fax in about 4 business days, weeks ahead of the printed CP-575 that follows by international mail. A founder who prefers to speak to an agent calls the international line at 267-941-1099 instead. The full non-resident sequence, including how the responsible party is named, is set out on the LLC EIN without SSN guide and the LLC-specific version on how to get an EIN for an LLC.
How Do You Contact the IRS About an EIN?
Call the Business and Specialty Tax Line at 800-829-4933, open weekdays 7 a.m. to 7 p.m. local time. International applicants call 267-941-1099, open 6 a.m. to 11 p.m. Eastern.
| IRS line | Number | Hours |
|---|---|---|
| Business and Specialty Tax Line | 800-829-4933 | Weekdays 7 a.m. to 7 p.m. local |
| International applicants | 267-941-1099 | Weekdays 6 a.m. to 11 p.m. Eastern |
| Fax, domestic | 855-641-6935 | 24 hours, return fax in 4 business days |
| Fax, international | 855-215-1627 | 24 hours, return fax in 4 business days |
Source: IRS contact directory, verified August 2026.
The Business and Specialty Tax Line is the number to call for anything about an existing EIN: to confirm the number, to correct a rejected application, or to request a 147C letter when the original CP-575 is lost. An agent verifies the caller as an authorized person on the account before releasing the number, then faxes or mails the 147C for $0. The call runs 20 to 40 minutes at busy times, so callers keep the legal entity name and mailing address on hand to clear verification on the first pass.
The IRS does not run a public EIN lookup, so a business confirms its own number through the 147C letter rather than a search box. The request steps are on the 147C letter guide, the ways to check a number you already hold are on how to verify an EIN, and the limits of any lookup are covered on EIN lookup.
Which IRS Forms and Letters Are Involved?
Three: Form SS-4 applies for the EIN, the CP-575 confirms it once, and the 147C replaces a lost CP-575. The IRS charges $0 for all 3.
Form SS-4 is the 1-page application. The CP-575 is the single confirmation letter the IRS mails when the EIN is assigned, and it is printed only once. A lost CP-575 is replaced by a 147C letter, requested free by phone. Each document is covered in full on IRS Form SS-4 PDF, LLC CP-575 letter, and EIN verification letter.
Form SS-4 carries 18 numbered lines, from the legal name on line 1 to the responsible party on lines 7a and 7b, the entity type on line 8a, and the reason for applying on line 10. The CP-575 reprints those details back to the business as the IRS record of the assignment. Two more IRS documents sit alongside these 3: Form 8822-B changes the responsible party or the mailing address on file, and the IRS asks that it be filed within 60 days of any such change. The 147C is the substitute the IRS issues when the CP-575 cannot be found.
An EIN is never truly deleted. When a business closes, the IRS closes the account tied to the number but keeps the EIN reserved to that entity forever, so it is retired rather than reassigned. The address and responsible-party update is walked through on Form 8822-B, closing the account is on how to cancel an EIN, and recovering a misplaced number is on lost LLC EIN.
This page states federal rules current as of August 2026. It is not legal or tax advice. Confirm your position with a licensed CPA or attorney.