Here’s how to get an EIN in Illinois, as of 2026: you apply free with the IRS online and get the number the same day, usually in about 15 minutes. Illinois doesn’t issue it, and third-party sites that charge $150 to $300 are selling a free federal service. The state step comes later, on MyTax Illinois.
What Is an Illinois EIN, and How Do You Get One?
An Illinois EIN is the free federal Employer Identification Number the IRS issues, not the state; you apply online in about 15 minutes, get it the same day, then register separately with the Illinois Department of Revenue for state tax accounts.
- Cost: $0 directly from the IRS; third-party filing sites charge $150 to $300.
- Apply: the IRS online EIN Assistant, or Form SS-4 by fax or mail if you can’t file online.
- Time: same day online, about four business days by fax, roughly four weeks by mail.
- State step: register with IDOR at 217-785-3707 or on MyTax Illinois using Form REG-1 for Illinois tax accounts such as withholding, sales, and use tax; if you hire employees, register with IDES for unemployment through MyTax Illinois or Form REG-UI-1.
Does Your Illinois LLC Need an EIN, or Just an IDOR Account ID?
Once you’ve formed your Illinois LLC, an EIN is the next federal step, though not every LLC must hold one.
| Business type | EIN required? | Notes |
|---|---|---|
| Single-member LLC, no employees | No, but recommended | Disregarded; banks and IDOR usually want it |
| Single-member LLC with employees | Yes | Payroll and employment tax |
| Multi-member LLC | Yes | Partnership by default |
| LLC taxed as S-corp or C-corp | Yes | The election requires it |
| Sole proprietor, no LLC | Sometimes | Only with employees or excise taxes |
| Partnership | Yes | Always files with an EIN |
One Illinois wrinkle is worth flagging: IDOR lets a single-member LLC register without a FEIN, but only on the paper Form REG-1. Getting the EIN first keeps you on the faster online path.
How to Get an EIN in Illinois From the IRS, Step by Step
Most Illinois owners finish the online application in about 15 minutes, and the steps match the current IRS EIN Assistant, including 2026 hours competitors still get wrong.
- Confirm your Illinois LLC is approved: the IRS needs the entity formed first. Check how long Illinois LLC approval takes before filing.
- Open the IRS EIN Assistant: it runs weekdays 6:00 a.m. to 1:00 a.m. ET, plus shorter weekend hours, not the 7:00 a.m. to 10:00 p.m. window guides still cite. It can’t be saved and times out after 15 minutes idle.
- Select the entity type: the screen that trips people up; match it to how the LLC’s taxed.
- Enter the legal name, then any DBA: the exact Illinois LLC name, plus an assumed name only if you use one.
- Name the responsible party: a natural person with an SSN or ITIN, since the IRS doesn’t accept nominees.
- Choose your reason: “started a new business” fits most new LLCs.
- Download the CP 575 immediately: the IRS won’t resend it, and recovering it later means a Letter 147C.
Illinois EIN Approval (EIN Confirmation Letter): Save the CP 575 Before MyTax Illinois
Once the IRS approves your Illinois EIN, the confirmation page gives you the number and lets you download the CP 575, the official EIN Confirmation Letter for your LLC. Save it right away and keep it with your Illinois Articles of Organization, Secretary of State file number, and operating records.
That letter matters in Illinois because the EIN is only the federal step. Before you can handle Illinois withholding, Retailers’ Occupation and Use Tax, or other state tax accounts, you still need to register through MyTax Illinois with the Illinois Department of Revenue. If you hire employees, the same state-side setup may also connect you with IDES for unemployment registration.
Do not confuse the CP 575 with your Illinois Account ID, Sales and Use Tax Account ID, withholding account, or IDES unemployment number. The CP 575 proves the IRS assigned your federal EIN; Illinois issues its own account numbers after state registration. If you skip the download, the IRS will not send another CP 575 copy, and you may have to request a 147C EIN verification letter instead.
Owners whose principal place of business sits outside the United States can’t use the Assistant; they apply by phone at 267-941-1099, fax, or mail.
Domestic filers can also fax Form SS-4 to 855-641-6935 (about four business days) or mail it to Cincinnati (roughly four weeks).
The EIN is free from the IRS, so a paid “filing service” adds cost without saving time; spend that on Illinois LLC formation costs instead. The IRS issues one EIN per responsible party per day.
The entity-type screen is where I’ve watched the most refiles happen. Owners pick “Limited Liability Company,” then answer the taxation follow-up wrong.
Don’t start the EIN screen until your Illinois LLC record is ready.
The IRS EIN application is free and fast, but it depends on details that should already be correct: your approved Illinois LLC name, tax classification, responsible party, and CP 575 download. If you still need formation help, registered agent service, or EIN filing support in one workflow, Northwest Registered Agent can help keep those steps organized before you move into Illinois tax registration.
What to Have Ready: Your Illinois LLC Name, SOS File Number, and Responsible Party
A few details before opening the Assistant keep the session from timing out. None’s hard to find once the LLC’s filed.
- Approved legal name: exactly as it reads on your Illinois Secretary of State record.
- Illinois SOS file number and formation date: both on your stamped Articles of Organization.
- Responsible party with SSN or ITIN: the person who controls the LLC.
- Business address: the LLC’s principal location.
Not sure the name’s an exact match? Look up your approved entity record first, and multi-member LLCs should settle their operating agreement too.
EIN vs Your Illinois Account ID, Withholding, and Sales Tax Numbers
An Illinois LLC can hold several numbers, and they aren’t interchangeable. The EIN is federal; the rest come from Illinois agencies.
| Category | IRS EIN (federal) | Illinois numbers (state) |
|---|---|---|
| Issued by | Internal Revenue Service | Illinois Department of Revenue, plus IDES |
| Used for | Federal taxes, payroll, banking, W-9 and 1099 | Withholding, Retailers’ Occupation and Use Tax, unemployment |
| Who needs it | Most LLCs, especially with staff or members | LLCs with Illinois tax duties or employees |
| Where to get it | IRS.gov, free | MyTax Illinois via Form REG-1 |
The state side isn’t one number. Illinois issues an Illinois Account ID (the IBT number), a Sales and Use Tax Account ID, a withholding account, and an IDES unemployment account, all separate from the EIN.
An Illinois EIN and an Illinois tax ID aren’t the same thing. A bank or vendor asking for your “tax ID” almost always means the EIN, not your Illinois LLC filings in Springfield.
Registering for Illinois Taxes Through MyTax Illinois After You Get Your EIN
The EIN unlocks the state layer. With it in hand, an Illinois LLC registers with the Illinois Department of Revenue on MyTax Illinois, using Form REG-1.
Illinois income tax withholding
Paying Illinois employees means registering for an Illinois withholding account with IDOR. The state rate’s 4.95 percent, and you’ll report it on Form IL-941.
Retailers’ Occupation Tax and Use Tax
Illinois doesn’t say “sales tax permit.” Selling, leasing, or renting taxable tangible personal property means registering for Retailers’ Occupation Tax and Use Tax. That yields a Certificate of Registration and a Sales and Use Tax Account ID. The rate’s 6.25 percent, dropping to 1 percent on drugs and medical appliances.
Retailers file Form ST-1, adding Form ST-2 for multiple sites. As of 2026, a remote retailer or marketplace facilitator registers at $100,000 in cumulative gross receipts from Illinois purchasers, and the old 200-transaction test is gone.
The state’s 1 percent low-rate grocery tax also ended January 1, 2026, though local grocery taxes can remain.
Service Occupation Tax
Service sellers that transfer tangible property have their own rule: from January 1, 2026, marketplace facilitators above $100,000 in service-sale receipts owe Service Occupation Tax.
Illinois unemployment insurance with IDES
Hiring triggers registration with the Illinois Department of Employment Security, within 30 days of startup, through MyTax Illinois or Form REG-UI-1. Most for-profit employers turn liable after $1,500 in wages in a quarter, or one worker for 20 weeks, then file the UI-3/40.
Personal Property Replacement Tax
Illinois adds a Personal Property Replacement Tax tied to classification, not a flat LLC fee: partnerships, trusts, and S corporations pay 1.5 percent, C corporations 2.5 percent. A disregarded single-member LLC isn’t filing it the same way, so don’t call it a universal franchise tax.
How to register, and what it costs
On MyTax Illinois, choose “Register a New Business (Form REG-1)”; your EIN‘s required, and online registration runs about one to two business days. The catch: paper REG-1 is slower, at about four to six weeks, or six to eight weeks if you mail the form.
Registration’s free, though some regulated categories carry license fees, and MyTax Illinois clears IDOR and IDES from one login. Afterward, your LLC still files its Illinois annual report and should keep an Illinois registered agent on record.
What most Illinois owners miss is simple: the EIN doesn’t register you with anyone in Springfield. I’ve seen clients wave a CP 575 and assume they’re set for sales tax, but they aren’t.
MyTax Illinois is the real door. If you sell online, recheck the 2026 threshold because the 200-transaction rule everyone cites is gone.
EIN and MyTax Illinois Registration Mistakes Illinois LLC Owners Make
Several errors recur on Illinois filings. Some are federal; the costlier ones are local.
- Assuming the EIN registers you with Illinois: it doesn’t; you still file REG-1 on MyTax Illinois.
- Paying for a free number: the IRS issues the EIN at no cost, so a “filing service” buys nothing.
- Using the dead 200-transaction test: for 2026, only the $100,000 receipts threshold applies.
- Calling Replacement Tax a franchise tax: it’s classification-specific and skips a disregarded single-member LLC.
- Name mismatch with the Secretary of State: the EIN name should match your Illinois record, or banks balk.
Finding a Lost EIN or Updating Your Illinois LLC With the IRS and IDOR
Losing the CP 575 isn’t fatal. The lost EIN still exists; you recover or re-verify it.
Check a prior federal return, an old bank application, or the original notice. The IRS Business and Specialty Tax Line issues a 147C verification letter, and you can also search a business’s EIN by name. Your Illinois numbers live elsewhere: the Illinois Account ID in MyTax Illinois and IDOR notices, the IDES account in wage reports.
Some changes need a new EIN; many don’t. A sole proprietorship becoming an LLC, or single-member turning multi-member, usually does.
A name or address change doesn’t: report those on Form 8822-B, and use Form 8832 to change how the LLC’s taxed.
Illinois EIN and Tax ID Questions, Answered
These Illinois EIN questions come up most often, from first-time filers and owners cleaning up an existing LLC.
Is an Illinois EIN the same as an Illinois tax ID number?
No. The EIN is federal, from the IRS. An “Illinois tax ID” usually means an IDOR Account ID, a Sales and Use Tax Account ID, a withholding account, or an IDES number.
Is getting an EIN in Illinois free?
Yes, applying directly with the IRS. Third-party sites charge a fee but can’t issue it any faster than IRS.gov.
Do single-member Illinois LLCs need an EIN?
Not always. A single-member LLC with no employees is a disregarded entity and isn’t federally required to have one. Most still get it, since registering with IDOR without a FEIN forces the slower paper REG-1.
Can a foreign-owned Illinois LLC get an EIN without an SSN?
Yes. Without an SSN or ITIN you can’t use the online tool. You can still file Form SS-4 by fax or mail, or phone 267-941-1099 if your business sits outside the United States.
Does Illinois have a sales tax permit?
Not by that name. Illinois registers retailers for Retailers’ Occupation Tax and Use Tax, issuing a Certificate of Registration with a Sales and Use Tax Account ID through MyTax Illinois.
What’s Illinois’s 2026 remote-seller threshold, and does my EIN cover it?
The EIN doesn’t cover it; that’s a separate state registration. As of 2026, a remote retailer or marketplace facilitator registers after $100,000 in cumulative gross receipts from Illinois purchasers, with no transaction-count test.
- Illinois Department of Employment Security: New Employer Registration
- IRS: Get an Employer Identification Number
- IRS: Employer Identification Number overview
- IRS: About Form SS-4
- Illinois Department of Revenue: Business Registration
- Illinois Department of Revenue: Registering Your Business for Sales and Use Tax
- Illinois Department of Revenue: FY 2026-12 Bulletin on Remote Retailer Thresholds
Looking for an overview? See Illinois LLC Services
Get Your Illinois LLC EIN with Harbor Compliance
Harbor Compliance helps Illinois LLC owners apply for an EIN correctly, avoid IRS filing errors, and stay prepared for MyTax Illinois, IDOR registration, payroll, and state compliance steps.
