EIN for LLC: Who Needs One, How to Apply, and Delays

To get an EIN for an LLC, apply directly with the IRS using Form SS-4 once your LLC has been approved by the state. The fastest route is the IRS online EIN assistant, which issues the number at the end of the session. Fax takes about four business days; mail takes roughly four weeks. The IRS never charges a fee, so skip any third-party site that asks you to pay.¹

Before You Apply

Your LLC has to exist in state records first. That means your Articles of Organization (called a Certificate of Formation in some states) must already be filed and approved. The IRS will not assign a tax ID to an entity that doesn’t yet exist.

Every application also names a “responsible party.” The IRS defines this as the person who owns or controls the entity and manages its funds and assets, directly or indirectly.² That person needs either a Social Security Number or an ITIN. For most LLCs, the responsible party is a member or manager.

Does Your LLC Actually Need One?

Multi-member LLCs always need an EIN, because the IRS treats them as partnerships by default and partnerships need a separate tax ID.

Single-member LLCs have a choice. A single-member LLC that is a disregarded entity, has no employees, and owes no excise taxes is not required to get an EIN and can use the owner’s SSN for federal tax purposes.³ Most still get one anyway. Banks typically require an EIN to open a business account,⁴ and some states require it for state tax registration. The moment a single-member LLC hires employees or has excise tax obligations, the EIN becomes mandatory.

What to Have Ready on Form SS-4

Every application uses IRS Form SS-4, no matter which submission method you choose.⁵ Gather this before you start:

The LLC’s legal name, matching your state formation documents character for character. A mismatch can delay processing or trigger rejection.
A physical mailing address where the IRS can send correspondence. A P.O. box alone may not be accepted for all fields.
The responsible party’s name and SSN or ITIN.
The reason for applying, such as starting a new business, hiring employees, or opening a bank account.
The number of LLC members. This drives the default tax classification: one member means disregarded entity; two or more means partnership.⁶

The Four Ways to Apply

Online

The IRS online EIN assistant is the fastest and most common method. It runs Monday through Friday, 6:00 a.m. to 1:00 a.m. (next day) Eastern; Saturday, 6:00 a.m. to 9:00 p.m.; and Sunday, 6:00 p.m. to midnight. You have to finish in one sitting, because progress cannot be saved and the session expires after 15 minutes of inactivity.⁷ Complete it, and your EIN appears on screen. You can download and print the confirmation immediately.

One rule cuts across every method: the IRS issues only one EIN per responsible party per day. If you need EINs for several entities, space the applications out.⁸

Fax

Fax a completed Form SS-4 to 855-641-6935 if your principal place of business is in the United States. Include a return fax number. Turnaround is about four business days, and the IRS faxes the EIN back to you.¹

Mail

Mail Form SS-4 to Internal Revenue Service, Attn: EIN Operation, Cincinnati, OH 45999. Expect roughly four weeks, which covers postal delivery both ways plus manual processing.¹

Phone (International Applicants Only)

If your principal place of business is outside the United States, you can apply by calling 267-941-1099, Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern. The number is not toll-free. Domestic LLCs cannot apply by phone.¹

Whichever method you use, the IRS mails a formal confirmation called Notice CP 575 to the address on your application. It lists your EIN, business name, and which federal tax forms your LLC must file. Keep it with your permanent records as official proof of the assignment.

What Slows Applications Down

The most common online snag is a mismatch between the responsible party’s name and Social Security Number. Even when your own records look right, the system may flag the application and require manual review.⁹ If that happens, try fax or mail, or call the IRS Business and Specialty Tax Line at 800-829-4933 to work through it.

Other errors are just system overloads during busy hours. The site will tell you to try again later; that isn’t a problem with your application.⁹

Before submitting, verify two things: the LLC’s legal name matches your state filing exactly, and the responsible party’s name and SSN match what the Social Security Administration has on file.

Having a CPA or Attorney Apply for You

You can authorize a CPA, attorney, or other professional to file for you by completing the Third-Party Designee section on Form SS-4. That authorizes the named person to answer IRS questions about the form and to receive the assigned EIN. The designee’s authority ends once the number is issued and does not extend to ongoing tax matters.¹⁰

One restriction: if the designee’s address or phone number matches the LLC’s, you cannot use the online application and must file by fax or mail. The CP 575 confirmation is always mailed to the taxpayer, not the designee.¹⁰

After You Have the EIN

By default, a single-member LLC is taxed as a disregarded entity and a multi-member LLC as a partnership.¹¹ If you want the LLC taxed as a corporation, file Form 8832.¹² If you want S corporation treatment, file Form 2553; for a calendar-year LLC, the general deadline is March 15 of the year the election takes effect, or any time in the preceding tax year.¹³ Changing tax classification does not require a new EIN.¹⁴

Most changes leave your EIN intact: a new business name, a new address, or a new tax election. You do need a new EIN if you terminate the LLC and form a new corporation or partnership, or if a single-member LLC that has been using the owner’s SSN must begin filing employment or excise tax returns. Converting a partnership into an LLC that stays classified as a partnership does not.¹⁴

If You Lose the Number

Check old tax returns, the paperwork from opening your business bank account, and any state or local license applications where you would have written the number down. If none of those turn it up, call the IRS Business and Specialty Tax Line at 800-829-4933, Monday through Friday, 7:00 a.m. to 7:00 p.m. local time (Alaska and Hawaii follow Pacific). After identity verification, the IRS can read the EIN to you over the phone or issue Letter 147C as official confirmation.¹

If you suspect someone is using your EIN fraudulently, such as a notice about a return you never filed or a balance you don’t owe, file Form 14039-B, the Business Identity Theft Affidavit, with the IRS right away.¹⁵

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Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
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Internal Revenue Service. Form SS-4 Application for Employer Identification Number
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Internal Revenue Service. Instructions for Form SS-4
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Taxpayer Advocate Service. When Taxpayers Struggle to Obtain an EIN, Everyone Loses
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Internal Revenue Service. Instructions for Form SS-4
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Internal Revenue Service. Form 8832 Entity Classification Election
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Internal Revenue Service. About Form 8832, Entity Classification Election
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