EIN Guide · What a federal EIN is, why your Illinois Corporation needs one, and how to get it.
EIN Guide for an Illinois Corporation
An Illinois corporation always needs its own federal Employer Identification Number — it cannot lean on an owner's Social Security number the way a solo LLC sometimes can. This guide explains what the EIN is, why a corporation must have one, exactly how to apply, and the mistakes that trip people up, including how non-US owners get one.
One price: $199.00/yr covers your formation, your registered agent, and your annual report, plus the $150.00 state filing fee, at cost.
State agency: Illinois Secretary of State, Department of Business Services
Annual report due: Anniversary of formation · Processing: 5-10 business days
✓ No hidden fees ✓ No second-year price hikes ✓ No missed filings
State facts
Illinois Corporation
What an EIN Is and Why a Corporation Must Have One
An Employer Identification Number is a nine-digit federal tax ID the IRS assigns to a business, formatted as XX-XXXXXXX. Think of it as a Social Security number for your corporation — the number that identifies the entity to the IRS, banks, and other institutions.
Why a corporation always needs one
A corporation is a separate taxpayer from its owners. It files its own federal return (Form 1120 as a C corporation, or 1120-S if it elects S status), and it needs an EIN to do so. Unlike a single-member LLC, which the IRS sometimes lets operate under the owner's Social Security number, a corporation has no such option — the entity is distinct by definition, so it must have its own tax ID from the start.
What you use the EIN for
- Filing the corporation's federal and Illinois tax returns
- Opening a corporate bank account — banks require the EIN, not a personal SSN
- Hiring employees and running payroll, including for owner-employees of an S corporation
- Applying for business licenses and permits
- Establishing business credit and vendor accounts
When to Apply — Timing It Right
The order in which you get your EIN matters, and getting it slightly wrong causes avoidable headaches.
Form the corporation first
Apply for the EIN after the Illinois Secretary of State approves your Articles of Incorporation, not before. The IRS application asks for the corporation's legal name and the state and date of formation, so the entity should legally exist first. Applying before the corporation is on file can produce a mismatch between the IRS record and the state record — the kind of discrepancy that surfaces later when a bank cross-checks your documents.
Get it before the bank account
You need the EIN before you can open the corporate bank account, and you need the bank account before you can genuinely separate corporate and personal finances. So the natural sequence is: Articles approved, EIN obtained, organizational meeting held and stock issued, bank account opened. Slotting the EIN into that order keeps everything moving without a stall.
Have your responsible party ready
The IRS application requires a "responsible party" — the individual who ultimately controls or manages the corporation, typically a principal officer. Have that person's name and taxpayer ID ready before you start, because the application is completed in a single session.
How to Apply for the EIN
The EIN is free directly from the IRS. Be wary of third-party sites that charge a fee to "obtain" an EIN — the number itself costs nothing when you apply through the IRS.
Online (the fast path)
The quickest route is the IRS EIN Assistant at IRS.gov. The online application:
- Takes roughly ten to fifteen minutes to complete
- Must be finished in one session — it times out if you step away too long
- Issues the EIN immediately on completion, so you can download the confirmation letter (CP 575) and use the number the same day
- Requires the responsible party to have a US Social Security number or ITIN
Online applications are available during the IRS's posted hours, and each responsible party is limited to one EIN per day.
By fax or mail (for those without an SSN or ITIN)
If the responsible party does not have a US Social Security number or ITIN — common for non-US owners — you cannot use the online tool. Instead, complete Form SS-4 and submit it by fax or mail. Fax responses typically come back within a few business days; mail takes longer. On Form SS-4, non-US applicants can write "Foreign" in the space for the taxpayer ID where appropriate.
Common EIN Mistakes and How to Avoid Them
The EIN process is simple, but a handful of recurring errors cause real friction with banks and the IRS.
Paying a third party for a free number
The most common mistake is paying a website that markets EIN "filing." The IRS issues EINs at no charge. A legitimate formation service may include EIN acquisition as a convenience, but the number itself is always free from the source.
Name mismatches
The name on your EIN application must exactly match the corporation's legal name on the Articles of Incorporation. A discrepancy — an abbreviation, a missing "Inc.," a typo — causes problems when a bank or the IRS reconciles your documents. File the corporation first, then copy the exact legal name into the EIN application.
Choosing the wrong entity type
The application asks what kind of entity you are. Select corporation (and indicate an S corporation election if you have made or will make one). Misclassifying the entity leads to the IRS expecting the wrong return and can create tax-filing confusion.
Losing the confirmation letter
The CP 575 confirmation letter is issued once. Save a digital copy and a printout in your corporate records, because banks and lenders frequently ask for it and the IRS does not casually reissue it — you would have to request a replacement (147C) letter, which is slower.
Applying too early
As noted, applying before the corporation is officially formed creates a record mismatch. Wait for the state's approval of the Articles before you request the EIN.
Frequently asked questions
Does my Illinois corporation need its own EIN?
Yes. A corporation is a separate taxpayer that files its own federal return, so it must have its own EIN — it cannot use an owner's Social Security number the way a single-member LLC sometimes can. You need the EIN to file taxes, open a corporate bank account, run payroll, and apply for licenses.
How much does an EIN cost?
Nothing. The IRS issues EINs free of charge. Be cautious of third-party websites that charge a fee to "get" your EIN — the number itself is always free when you apply directly through the IRS. A formation service may include EIN acquisition as a convenience, but you are never required to pay the IRS for the number.
Can I get an EIN before my corporation is approved?
You should wait until the Illinois Secretary of State approves your Articles of Incorporation. The EIN application asks for the corporation's legal name and formation details, so the entity should exist first. Applying beforehand can create a mismatch between the IRS and state records that causes problems when a bank verifies your documents.
How do I get an EIN if I'm not a US resident?
If your responsible party has no US Social Security number or ITIN, you cannot use the online tool. Instead complete Form SS-4 and submit it to the IRS by fax or mail; fax responses typically return within a few business days. Non-US applicants can indicate "Foreign" in the taxpayer ID field where appropriate. A non-US resident can fully own an Illinois corporation.
How long does it take to get an EIN?
Online, the EIN is issued immediately — you finish the application and download the confirmation letter the same day. By fax, expect a few business days; by mail, several weeks. The online route is by far the fastest, but it is only available to responsible parties who have a US Social Security number or ITIN.
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