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Form SS-4: how to apply for an EIN online, by fax or mail, line-by-line tips and timing
Form SS-4 is the IRS application for a free 9-digit EIN. Who must file, when to apply, online hours, fax numbers and mailing addresses, processing times (immediate, 4 business days, 4 weeks), the responsible party rule and common errors.
Prepared by Aldro Accounting · Updated · Sources checked
The quick answer
Form SS-4, Application for Employer Identification Number, is how a business gets a free 9-digit EIN from the IRS. A U.S.-based applicant can apply online and use the EIN immediately. By fax it generally takes 4 business days, and by mail about 4 weeks.
What Form SS-4 is
Use Form SS-4 to apply for an EIN. An EIN is a 9-digit number, for example 12-3456789, assigned to sole proprietors, corporations, partnerships, estates, trusts and other entities for tax filing and reporting.
There's no fee. The IRS warns about websites that charge for an EIN and says you never have to pay one.
EIN issuances are limited to one per responsible party per day. Use only one application method for each entity so you don't end up with two EINs.
Who needs to file Form SS-4
File Form SS-4 if the entity doesn't already have an EIN but must show one on any return, statement or other document.
A partnership, corporation, REMIC, nonprofit organization or farmers' cooperative must use an EIN for any tax purpose, even with no employees.
Don't apply for a new EIN if the existing entity only changed its business name, elected on Form 8832 to change how it's taxed, or ended as a partnership because of a sale or exchange of 50% or more of its interests.
If you're forming a corporation or LLC, form it with the secretary of state first. Applying before the state filing can delay the EIN.
Online, fax, mail or phone
Apply early enough to have the EIN when a return, statement or tax deposit is due.
Online: if you have a legal residence, principal place of business or principal office in the United States or U.S. territories, you can get an EIN online and use it immediately. The tool is open Monday to Friday 6:00 a.m. to 1:00 a.m. the next day, Saturday 6:00 a.m. to 9:00 p.m., and Sunday 6:00 p.m. to midnight, Eastern Time. Finish in one session: it can't be saved and expires after 15 minutes of inactivity.
Scroll sideways to see all columns.
| Method | Applicants in the 50 states or DC | Applicants in a U.S. territory or abroad | Timing |
|---|---|---|---|
| Online | Available | U.S. territories only | Immediate |
| Fax (Fax-TIN) | 855-641-6935 | 855-215-1627 from within the U.S., 304-707-9471 from outside | Generally within 4 business days |
| Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999 | Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999 | About 4 weeks. Send 4 to 5 weeks before you need it | |
| Phone | Not available | 267-941-1099 (international applicants) | During the call |
Phone: the IRS no longer issues EINs by phone to domestic taxpayers. International applicants with no U.S. residence or principal place of business can call 267-941-1099, Monday to Friday, 6:00 a.m. to 11:00 p.m. Eastern. If the IRS asks, the signed SS-4 must be mailed or faxed within 24 hours.
Line-by-line tips
Follow each line's instructions and generally enter N/A on lines that don't apply. That avoids IRS requests for more information.
- Line 1: the legal name exactly as on the Social Security card, charter or other legal document. A sole proprietor enters their individual name, not the business name, with no abbreviations or nicknames.
- Line 2: the trade or business name. Use only the legal name, or only the trade name, on all tax returns to prevent delays.
- Lines 4a-5b: the mailing address, and the physical address only if different. No P.O. box on line 5. Foreign addresses need city, province or state, postal code and the full country name.
- Line 7a: the responsible party must be an individual, a natural person, not an entity, unless the applicant is a government entity.
- Line 7b: enter "foreign" or N/A if the responsible party doesn't have and can't get an SSN or ITIN.
- Line 14: check it to file Form 944 once a year instead of Form 941 quarterly if you expect employment tax of $1,000 or less for the year, which generally means $5,000 or less in total wages ($6,536 or less in a U.S. territory).
If a return is due before the EIN arrives
Write "Applied For" and the date you applied in the space for the number. Don't put your SSN on a return as an EIN.
If a tax deposit is due first, make the check or money order payable to the "United States Treasury" and show your name as on Form SS-4, your address, the type of tax, the period covered and the date you applied.
Call 800-829-4933 to verify a number or ask about a mailed application.
After you have an EIN
Report a change of responsible party, address or location on Form 8822-B. Changes in responsible parties must be reported within 60 days.
Leaving out a required TIN on a return, statement or other document, yours or another person's, can cost $50 for each failure.
A draft December 2026 revision of Form SS-4 asks all entity types on line 9b to name the state or foreign country where they were created, and warns on line 14 that picking the Form 944 option wrongly can delay processing.
Once the business has its EIN, Aldro's flat yearly price covers every federal and state business return it needs for the year. Our team prepares and files them.
Worked example
Dev forms a single-member LLC with his state on March 2 and wants to open a business bank account. He applies online on a Saturday morning, enters his own name as the responsible party on line 7a, and gets the EIN at the end of the session. Had he mailed Form SS-4 instead, the IRS says to send it 4 to 5 weeks ahead and expect the number in about 4 weeks. If his first return came due before a mailed EIN arrived, he would write "Applied For" and the date, not his SSN.
Common questions
How much does it cost to get an EIN?
Nothing. The IRS says you never have to pay a fee for an EIN.
How long does Form SS-4 take?
Online is immediate. Fax generally takes 4 business days. Mail takes about 4 weeks.
Can I get an EIN by phone?
Only international applicants with no U.S. residence or principal place of business, at 267-941-1099. The IRS no longer issues EINs by phone to domestic taxpayers.
Who is the responsible party on Form SS-4?
An individual, a natural person, not an entity, unless the applicant is a government entity.
Is there a due date for Form SS-4?
No fixed date. Apply early enough to have the EIN when a return, statement or deposit is due.
How do I change the responsible party later?
File Form 8822-B within 60 days of the change.
The cheapest way to get your business taxes done: $399 flat.
Business tax filing is $399 USD a year, and it covers everything tax for that year.
How it works
- Tell us about your business. A two-minute form. No payment is collected through it.
- Get your next steps by email. We’ll email you the next steps within one business day. After you sign up we’ll send you a secure upload link for your documents.
- We file it. Our team prepares and files your return. Add bookkeeping for $20 a month if you want it.
What's included
$399 a year covers everything tax for that tax year.
- Every business return for the year. All the federal and state or provincial business returns you need for the tax year: Schedule C, 1065, 1120-S, 1120 and their state returns in the US; T2, or T1 with T2125, in Canada.
- More than one state. Multi-state returns are included at the same price.
- Your personal return. The owner’s personal return (1040 or T1) is included when it’s needed for the business income.
- Quebec. Quebec returns (CO-17, TP-1 and TP-80) are included. Our Quebec pages are in French, and our team works with you in English.
- Extensions and reminders. Extensions (Form 7004 or 4868) and quarterly estimate reminders are included.
- Information returns. 1099-NEC, T4/T4A and T5018 slips are included in the tax price.
- City and excise returns. City and local business tax returns, and state excise returns such as Washington B&O, are included in the yearly price.
- Franchise tax reports. State franchise tax reports, such as the Texas franchise tax report, are included.
- Estimated tax and instalment amounts. We work out your quarterly estimated tax payments in the US, or your CRA instalments in Canada, and tell you what to pay and when.
- Unfiled past years. Each unfiled prior-year return is $399 per tax year, the same flat price.
- Bookkeeping at $20 a month. Unlimited bank and card accounts, monthly reconciliation and monthly statements.
Basic inventory tracking for online stores, such as Shopify, is included. Full cost-of-goods reconciliation is quoted separately. Payroll processing and sales-tax filing aren’t included in bookkeeping. Prices are in USD. Our team prepares and files your return.
Sources
- IRS: Form SS-4 · checked October 31, 2026
- IRS: Instructions for Form SS-4 · checked October 31, 2026
- IRS: Draft Form SS-4 (Rev. December 2026) · checked October 31, 2026
- IRS: About Form SS-4 · checked October 31, 2026
- IRS: Get an employer identification number · checked October 31, 2026
- IRS: Publication 583 · checked October 31, 2026
This guide explains general rules from the sources listed. It isn’t tax advice for your situation.