An EIN, or Employer Identification Number, is a nine-digit tax ID issued by the IRS to identify a business — not by the Social Security Administration. The phrase “SSA EIN number” is a common mixup: the SSA issues Social Security Numbers to individuals, while the IRS issues EINs to businesses, estates, trusts, and other entities. Applying is free, and the IRS online tool issues the number immediately once your information checks out.1Internal Revenue Service. Get an Employer Identification Number
Why the SSA Comes Up in EIN Searches
The confusion is understandable. Every employer uses its EIN to report wages and deposit the FICA taxes that fund Social Security and Medicare. The IRS collects those filings and shares the wage data with the SSA so that each employee’s earnings get credited toward future benefits.
The main reporting form is Form 941, the Employer’s Quarterly Federal Tax Return, which covers federal income tax, Social Security tax, and Medicare tax withheld from paychecks along with the employer’s matching share.2Internal Revenue Service. About Form 941, Employer’s Quarterly Federal Tax Return At year-end, employers issue W-2s to employees and transmit copies to the SSA. The EIN appears on every one of those documents, tying the wages back to the business that paid them. So while the SSA sees your EIN constantly, it does not assign it.
Who Needs an EIN
Any business with employees needs an EIN. Corporations, partnerships, and multi-member LLCs must have one whether they have employees or not. The IRS also requires EINs for entities that pay excise taxes, administer certain retirement plans, or operate as trusts or estates.1Internal Revenue Service. Get an Employer Identification Number
A sole proprietor or single-member LLC with no employees can legally use the owner’s SSN. But the moment you hire even one employee, or change your structure by incorporating or taking on a partner, an EIN is required. Nonprofits, churches, and other tax-exempt organizations generally need one too, and each organization should have only one EIN and use it from year to year.3Internal Revenue Service. Employer Identification Numbers for Tax-Exempt Organizations
Even when the law doesn’t require one, many sole proprietors get an EIN anyway. Using it instead of your SSN on vendor forms and account applications keeps your personal number out of circulation and makes banking and bookkeeping cleaner.
How to Apply Online
The IRS online application is free and delivers the EIN immediately.1Internal Revenue Service. Get an Employer Identification Number Before you start, have two things ready:
- The legal structure of your entity (corporation, LLC, partnership, and so on).
- The identity of the “responsible party” — the person with ultimate ownership or control — along with their valid SSN or ITIN.
The tool walks you through questions about your business type, legal name, address, and reason for applying. When you finish, the system validates the entries and displays your new EIN on screen. Print or save that confirmation page right away. The IRS mails a formal notice (CP 575) later, but having the number in hand lets you open a bank account or file returns without waiting.
The online system is not open around the clock. It runs Monday through Friday from 6:00 a.m. to 1:00 a.m. the following day, Saturdays 6:00 a.m. to 9:00 p.m., and Sundays 6:00 p.m. to midnight, all Eastern time.1Internal Revenue Service. Get an Employer Identification Number Try outside those hours and you’ll get an error. The IRS also limits issuance to one EIN per responsible party per day, regardless of the application method.4Internal Revenue Service. Publication 1635 – Understanding Your EIN
Fax and Mail
If the online tool doesn’t fit your situation, you can submit Form SS-4 by fax or mail. Faxing generally returns your EIN within four business days as long as you include a return fax number. For applicants in the 50 states or D.C., the fax number is 855-641-6935.5Internal Revenue Service. Where to File Your Taxes for Form SS-4 Mailing the paper form is the slowest route; the IRS advises submitting it at least four to five weeks before you need the number.6Internal Revenue Service. Instructions for Form SS-4
Applying Without a Social Security Number
Foreign individuals and entities without an SSN can still get an EIN, but not through the online tool. The IRS restricts the online system to applicants whose principal business or legal residence is in the U.S. or a U.S. territory.7Internal Revenue Service. Instructions for Form SS-4 Outside that requirement, your options are phone, fax, or mail.
Phone is reserved for international applicants with no legal residence, principal business, or office in the U.S. Call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern time.7Internal Revenue Service. Instructions for Form SS-4 The number is often issued during the call. For fax submissions from outside the U.S., use 304-707-9471.5Internal Revenue Service. Where to File Your Taxes for Form SS-4 A responsible party with an ITIN rather than an SSN can still apply. If they have neither, they may need to obtain an ITIN first using Form W-7.
If You’ve Lost Your EIN
Losing track of an EIN happens more often than you might expect, especially with entities set up years ago. Start with your own paperwork: past tax returns, the original IRS assignment notice (CP 575), or bank records where the number appears. If none of that turns up the number, you have two options. You can request a business entity transcript through the IRS website, or call the Business and Specialty Tax Line at 800-829-4933 and ask for Letter 147C, which confirms the previously assigned EIN.8Internal Revenue Service. Employer Identification Number The IRS verifies identity before releasing the information, so have basic entity details on hand.
Keeping Your EIN Information Current
An EIN is permanent for the entity it was assigned to. Simple changes — a new business address, a new business name, a new responsible party — don’t require a new number. You update the IRS instead by filing Form 8822-B.9Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business
One deadline to watch: a change in the responsible party must be reported within 60 days. Missing that window is a quiet compliance failure that surfaces later, often when the IRS sends correspondence to the wrong person or a bank asks for updated records.
Certain structural changes are different. If a sole proprietor incorporates, a partnership converts to a corporation, or an estate creates a separate trust, the IRS treats the result as a new entity that needs its own EIN.10Internal Revenue Service. Do You Need a New Employer Identification Number? Most routine changes don’t trigger this; check the IRS list for your entity type if you’re restructuring.