How to Get a Tax ID for an LLC: Online, Fax, or Mail

To get a tax ID for an LLC, form the LLC at the state level first, then apply for an Employer Identification Number (EIN) directly with the IRS. The fastest route is the free online application at IRS.gov, which issues the nine-digit number as soon as you finish.¹ The IRS never charges a fee. If a site asks you to pay, you’re not on the IRS site.

An EIN works like a Social Security Number for your business. You’ll use it on federal tax filings, on W-9s and vendor paperwork instead of your personal SSN, and when opening a business bank account. The IRS treats an EIN as required for any LLC, including a single-member LLC with no employees.²

What to Have Ready Before You Apply

Your LLC has to exist as a legal entity before you apply. That means your articles of organization or certificate of formation is already filed and accepted by your state. Apply before the LLC is formed and the IRS will reject you.

Have this on hand:

The legal name of the LLC, exactly as it appears on your formation documents, plus any DBA or trade name.
The responsible party: the person who controls or manages the LLC and its assets. This person must have a valid SSN or ITIN, unless you’re a non-U.S. applicant (covered below).³
A physical mailing address for IRS correspondence.
A short description of the business activity, such as “consulting” or “online retail.”
The number of members: one, or more than one.
The reason for applying (new business, hiring employees, and so on).

Never list a nominee (someone who doesn’t actually control the LLC) as the responsible party. The IRS warns this can expose your information to unauthorized people.⁴

Pick Your Tax Classification Before You Start

This is where LLC applicants get tripped up. An LLC is not its own tax category to the IRS. The IRS assigns a default based on member count: a single-member LLC is a “disregarded entity” whose income flows to the owner’s personal return, and a multi-member LLC defaults to partnership taxation, filing an informational return with each member reporting their share.⁵

You can override either default by filing Form 8832 to elect corporate treatment, or Form 2553 for S-corporation status. Decide before you start the EIN application, because line 9a of Form SS-4 asks you to declare it. For a single-member LLC keeping the default, check “Other” and write “disregarded entity.” For a multi-member default, check “Partnership.” If you’ve elected corporate treatment, check “Corporation.”³ The default classification works fine for most new LLCs, and you can change it later.

How to Submit the Application

The application itself is IRS Form SS-4.⁶ Online, you never see the paper form; the system asks the same questions in a guided format. You have three submission options.

Online, With Immediate Issuance

The IRS online EIN tool issues your number the moment you finish, and you can download and print the confirmation on the spot. That printout is functionally the same as the CP 575 notice the IRS mails later. Save a copy.

Hours are all Eastern Time:

Monday through Friday, 6:00 a.m. to 1:00 a.m. the next day.
Saturday, 6:00 a.m. to 9:00 p.m.
Sunday, 6:00 p.m. to midnight.

If you hit an error (reference numbers 101 and 115 are the common ones), the system either directs you to call a representative or prompts you to fix specific fields and resubmit.

Fax, About Four Business Days

Complete and sign Form SS-4 and fax it to the IRS. The fax number depends on whether your principal office is in the United States or abroad. Include a return fax number, and you’ll generally get your EIN back within four business days.³

Mail, About Four to Five Weeks

Mail the signed Form SS-4 to the service center listed in the instructions. Processing and the return CP 575 notice take roughly four to five weeks.³ Store the CP 575 permanently with your formation documents; it’s your official proof the EIN was assigned.

If You’re Outside the U.S. or Don’t Have an SSN

The online tool is restricted to applicants with a legal residence, principal place of business, or principal office in the United States.³ If that’s not you, you have three routes:

Phone: call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern Time. The caller must be authorized to receive the EIN and answer questions about the form. Have a completed Form SS-4 ready. If asked, mail or fax the signed form within 24 hours.
Fax: 304-707-9471. Response within about four business days.
Mail: Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999. Allow about four weeks.

On line 7b, where the responsible party’s SSN or ITIN goes, enter “foreign” or “N/A” if the responsible party doesn’t have one and isn’t eligible for one.³

Having Someone Else Apply for You

An attorney, accountant, or other representative can submit the application by completing the “Third Party Designee” section on line 18. The LLC owner still signs the form. The designee’s authority is narrow: they can answer IRS questions about the application and receive the assigned EIN, and it ends the moment the number is issued.³

One catch: if the designee’s address or phone number matches the LLC’s, the IRS won’t process the application online or by phone. Use fax or mail in that case.

Keeping the EIN and Knowing When You Need a New One

Your EIN generally stays with the LLC for its life. A name change, address change, or new member does not require a new number. Certain structural changes do:⁷

You terminate the LLC and form a new corporation or partnership.
You own a single-member LLC and need to begin filing employment or excise tax returns.

When the responsible party or the LLC’s address changes, notify the IRS within 60 days by filing Form 8822-B.⁸ This step gets skipped often. When it does, IRS notices go to an old address, the EIN stays linked to someone who no longer controls the business, and account access gets complicated.

The EIN is only the federal piece. Depending on your state, you may also need a separate state tax ID, particularly if you’ll collect sales tax or run payroll, and many states require annual or biennial reports with the secretary of state’s office. Those are separate from the EIN process and vary by jurisdiction.

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Internal Revenue Service. Get an Employer Identification Number
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Internal Revenue Service. Employer Identification Number
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Internal Revenue Service. Instructions for Form SS-4 (12/2025)
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Internal Revenue Service. Responsible Parties and Nominees
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Internal Revenue Service. LLC Filing as a Corporation or Partnership
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Internal Revenue Service. About Form SS-4, Application for Employer Identification Number (EIN)
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Internal Revenue Service. When to Get a New EIN
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Internal Revenue Service. About Form 8822-B, Change of Address or Responsible Party – Business