Getting an EIN for Your Illinois LLC

An Employer Identification Number is a nine-digit number the IRS assigns to identify a business for federal tax purposes. People also call it a Federal Employer Identification Number (FEIN) or a federal tax ID. Whatever the name, it functions as the business equivalent of a Social Security number — it identifies your Illinois LLC to the IRS, to banks, and to other institutions.

What you use it for

• Filing federal taxes — depending on how your LLC is taxed, the EIN appears on partnership returns, corporate returns, or payroll filings.
• Opening a business bank account — nearly every bank requires an EIN to open an account in the LLC's name.
• Hiring employees — you need an EIN to report payroll taxes and file employment tax returns.
• Building business credit — vendors and lenders often use the EIN to identify your business separately from you personally.

Why it matters for liability protection

An EIN also supports the separation between you and your LLC that keeps your liability shield intact. Using an EIN and a dedicated business bank account — rather than running everything through your Social Security number and personal accounts — is part of demonstrating that the LLC is a genuine separate entity. That separation is exactly what courts look at when someone tries to reach your personal assets.

Not every single-member LLC is technically required to have an EIN, but in practice almost every LLC benefits from getting one. Here is how to think about it.

When an EIN is required

• Multi-member LLCs — if your LLC has more than one member, it files a partnership return and must have an EIN. There is no way around it.
• LLCs with employees — the moment you hire, you need an EIN to handle payroll and employment taxes.
• LLCs that elected corporate taxation — if you elected S-corporation or C-corporation treatment with the IRS, you need an EIN.

When it is technically optional but still smart

A single-member LLC with no employees that is taxed as a disregarded entity can, in theory, use the owner's Social Security number for federal tax purposes. But almost every advisor recommends getting an EIN anyway, for two practical reasons. First, most banks require an EIN to open a business account, and separating your finances is essential to protecting your liability shield. Second, using an EIN keeps your Social Security number off business paperwork, W-9s, and vendor forms, which reduces your exposure to identity theft.

For the small effort involved — the application is free and takes minutes — there is rarely a good reason for an Illinois LLC to skip getting an EIN.

The important thing to know up front: an EIN is free, and you get it directly from the IRS. You never have to pay the government for one.

The online application

The fastest and most common route is the IRS online EIN Assistant at IRS.gov. The application takes about ten minutes, and if you complete it successfully, the IRS issues your EIN immediately — you can download and print the confirmation letter and use the number the same day. A few practical notes:

• The online tool is available only during IRS operating hours, not around the clock.
• You must complete the application in one session; it does not save partway through.
• You need a valid Social Security number or ITIN as the "responsible party" to file online.

If you can't apply online

Non-U.S. residents without an SSN or ITIN cannot use the online tool. Instead, you complete Form SS-4 and submit it by fax or mail. Fax is faster than mail — expect a wait measured in business days rather than the instant online result. International applicants can also apply by phone in some cases.

Wait until your LLC is approved

Apply for the EIN after your Articles of Organization are approved and your LLC officially exists, not before. The EIN application asks for your LLC's legal name and details as they appear in the state record, so having the LLC formed first keeps everything consistent. If you apply too early and your name changes, you can end up with a mismatch to untangle.

Getting an EIN is simple, but a handful of avoidable missteps cause headaches. Knowing them in advance saves you time and money.

Paying a third party for a free number

The most common mistake is paying someone to "get your EIN." The IRS charges nothing. If a service bundles EIN acquisition into a formation package, understand that the government fee is zero — you are paying only for the convenience of not spending ten minutes yourself. There is no faster or more official EIN than the one you get directly from the IRS.

Applying before the LLC exists

Requesting the EIN before your Articles of Organization are approved can create a mismatch between the IRS record and the state record. Form the LLC first, confirm the exact legal name in the state's system, then apply.

Choosing the wrong tax classification on the application

The EIN application asks how your LLC will be taxed. Answer it accurately for your situation — a single-member disregarded entity, a multi-member partnership, or a corporation if you have made that election. If you plan to elect S-corporation treatment, that is a separate IRS election; the EIN application alone does not make the election.

Losing your confirmation letter

When the IRS issues your EIN, save the confirmation (the CP 575 letter for online applicants) somewhere permanent. Banks and other institutions sometimes ask for it, and getting a replacement is more of a hassle than simply keeping the original. Store a copy with your Articles of Organization and operating agreement so your core LLC documents live together.