Getting an EIN for Your Arizona LLC

An Employer Identification Number (EIN) is a nine-digit number the IRS issues to identify a business for federal tax purposes. Think of it as a Social Security number for your Arizona LLC — you use it on tax filings, to open business bank accounts, to hire employees, and to establish the company's identity with the IRS and other institutions.

The EIN is a federal item, not an Arizona one. It comes from the IRS regardless of which state your LLC is formed in, so the process is the same for an Arizona LLC as for any other. Where Arizona comes in is on the state side — TPT licensing, income tax — and those accounts often ask for your EIN, which is one reason to get it early.

When your Arizona LLC needs an EIN

• Multi-member LLCs must have one. A multi-member LLC files a partnership return (Form 1065), and that requires an EIN — no exceptions.
• Any LLC with employees needs one to handle payroll and employment taxes.
• Opening a business bank account effectively requires one — nearly every bank asks for the EIN rather than letting you use a personal SSN.
• Electing S-corp or C-corp taxation requires an EIN to file the corporate-style returns.

Single-member LLCs

A single-member LLC with no employees can technically use the owner's Social Security number for federal income tax, because the IRS treats it as a disregarded entity. But almost every advisor recommends getting an EIN anyway. It keeps your SSN off business paperwork and vendor forms, it's required by most banks, and it makes the business look and operate like the separate entity it is — which supports your liability protection.

The IRS issues EINs at no cost. You never have to pay a fee to the IRS for one, and any site charging you just to "get an EIN" is charging for a form you can complete yourself for free. Here's how the application actually works.

Online — the fastest route

The online EIN Assistant at IRS.gov is the quickest method. You complete the application in one session (it can't be saved and resumed), and the EIN is issued immediately on completion — you can download the confirmation letter (CP 575) and start using the number the same day.

To apply online, the responsible party must have a valid US taxpayer ID — a Social Security number or an Individual Taxpayer Identification Number (ITIN). The online tool is available during set hours on the IRS's schedule, so apply during a weekday session for the smoothest experience.

What you'll need on hand

• Your LLC's exact legal name as filed in the Arizona Articles of Organization
• Your LLC's Arizona formation/mailing address
• The name and taxpayer ID of the responsible party (usually a member)
• The number of members and the LLC's expected tax classification
• Your reason for applying (started a new business)

Timing tip

Wait until your Arizona LLC is actually approved by the Corporation Commission before applying for the EIN, so the LLC's legal name is finalized and matches. Applying with a name that doesn't yet exist — or that changes when the ACC finalizes it — creates a mismatch you'll have to correct later.

Non-US residents and others without an SSN or ITIN can still get an EIN for an Arizona LLC — you just can't use the online tool, which requires a US taxpayer ID for the responsible party.

The fax or mail route

Complete IRS Form SS-4 by hand and submit it by fax or mail. On the responsible-party line, you can indicate "foreign" where a US taxpayer ID would go. Fax is considerably faster than mail — the IRS typically returns the EIN by fax within a few business days if you provide a return fax number, whereas mail can take several weeks.

What to expect

• There's no online instant issuance for this path — plan for the processing time.
• Double-check the form; errors on a faxed or mailed SS-4 cause delays that are slower to fix than an online correction.
• You do not need a US address to obtain an EIN, but you do need a valid Arizona statutory agent and known place of business for the LLC itself.

This path is common for non-resident owners forming an Arizona LLC, and it works — it just takes more patience than the instant online option available to those with an SSN or ITIN.

The EIN is issued once and stays with your Arizona LLC permanently. A few things to do — and not do — once you have it.

Put it to work

• Open your business bank account. Bring the EIN confirmation, your filed Articles of Organization, and your operating agreement. Separating business and personal finances is what keeps your liability shield intact.
• Set up Arizona tax accounts. If you'll sell taxable goods or services, use the EIN when you register for Transaction Privilege Tax with the Arizona Department of Revenue and for any city business registration.
• Use it on federal filings. The EIN goes on your LLC's federal returns — Form 1065 for multi-member, Schedule C for single-member, Form 1120-S for an S-corp election.
• Provide it on W-9s. Vendors and clients who pay your LLC will ask for the EIN on a W-9 instead of your SSN.

Keep it safe and consistent

Store the CP 575 confirmation letter somewhere secure — it's the official proof of your EIN, and the IRS won't reissue that specific letter (though they can provide a confirmation letter, 147C, on request). Use the exact legal name that matches the EIN on all filings to avoid mismatches with the IRS.

When you need a new EIN

Usually you don't. A change of business name, address, or statutory agent does not require a new EIN. You generally only need a new one if the entity's structure fundamentally changes — for example, certain conversions or a change in the number of members that alters the tax classification in specific ways. For most Arizona LLCs, the EIN you get at formation is the one you keep for the life of the company.