To sell online in Illinois, you don’t need a “business license” in the sense of one all-purpose permit, because the state doesn’t issue one. What you do need is a Certificate of Registration from the Illinois Department of Revenue once your sales create a tax connection to the state, and depending on your setup, a county DBA filing and a local city or county license may apply on top of that. The registration itself is free, and most sellers finish it online in a day or two.
The Certificate of Registration Is the Core Document
The Certificate of Registration is what actually authorizes you to sell tangible goods at retail in Illinois. State law makes it illegal to sell at retail without one.1Illinois General Assembly. Illinois Compiled Statutes 35 ILCS 120 – Retailers Occupation Tax Act The certificate lets you collect and remit sales tax on transactions with Illinois customers, and the Department of Revenue issues it at no charge through your MyTax Illinois account after your application is processed.2Illinois Department of Revenue. Business Registration
Functionally it works more like a tax account number than a traditional license. The state wants a record of your business so it can track the sales tax you owe. Operating without one is illegal and exposes you to penalties that come out of your own pocket, not your customers’.
When You Actually Have to Register
You don’t need to register the moment you list an item online. Registration is triggered when your business establishes a connection Illinois tax law recognizes. That connection is called nexus, and it comes in two forms.
If you have a physical presence in Illinois — a store, office, warehouse, employees, or a home you sell from — you have nexus from your first sale. Sellers based in the state fall into this category automatically.
If you’re located outside Illinois, the trigger is economic nexus. As of January 1, 2026, you must register once your total sales to Illinois customers reach $100,000 or more over the prior 12 months. Illinois used to have a second trigger at 200 separate transactions, but that threshold was eliminated at the start of 2026.3Illinois Department of Revenue. FY 2026-12 Destination-Based Retailers Occupation Tax Changes
Out-of-state sellers are expected to check their Illinois sales quarterly, at the end of March, June, September, and December, measuring the preceding 12 months.4Cornell Law Institute. Illinois Administrative Code Title 86 Section 150.803 Once you cross the line, you register and begin collecting for the following year.
If You Only Sell Through Amazon, eBay, or Etsy
Major marketplaces are classified as “marketplace facilitators” under Illinois law, which means the platform collects and remits Illinois sales tax on your behalf. You don’t report those marketplace sales on your own return.5Illinois Department of Revenue. Frequently Asked Questions for Marketplace Facilitators Marketplace Sellers and Remote Retailers
Here’s the catch. If you also sell through your own website, at craft fairs, or through any channel that isn’t a marketplace facilitator, those direct sales are your responsibility. That means you still need your own Certificate of Registration and still file returns covering the non-marketplace portion of your business. A seller who lives entirely on one marketplace and never sells elsewhere has the simplest picture. The moment you add a Shopify store or a booth at a local fair, you need to register.
How to Register With the Department of Revenue
Registration uses Form REG-1, the Illinois Business Registration Application. Before you start, have this information ready:
- Your Federal Employer Identification Number, or your Social Security Number if you’re a sole proprietor.
- Your legal business name, any assumed name (DBA), your primary business address, and your business structure (sole proprietorship, LLC, corporation, etc.).
- The date you started or plan to start business activities in Illinois.
- Your six-digit NAICS code, the industry classification that describes what your business does.
The fastest route is the MyTax Illinois portal at mytax.illinois.gov, where you select “Register a New Business” on the homepage. Processing usually takes one to two business days.2Illinois Department of Revenue. Business Registration Paper filers can mail Form REG-1 to the Central Registration Division, Illinois Department of Revenue, PO Box 19030, Springfield, IL 62794-9030, but paper takes four to six weeks.6Illinois Department of Revenue. REG-1 Illinois Business Registration Application
One timing note. The Department expects you to register before you make sales, purchases, or hire employees in the state.2Illinois Department of Revenue. Business Registration Don’t push it off until the first tax deadline.
Filing an Assumed Business Name (DBA) With Your County
If you operate under any name other than your own legal name, Illinois requires you to file an assumed business name certificate with the county clerk in the county where you do business. This applies to sole proprietorships, general partnerships, and professional service corporations.7Illinois General Assembly. Illinois Compiled Statutes 805 ILCS 405 – Assumed Business Name Act
Filing fees can run as low as $10 in some counties. The statute also requires you to publish notice of the filing in a local newspaper once a week for three consecutive weeks, starting within 15 days of filing, then submit proof of publication back to the county clerk within 50 days. Skip the publication step and the assumed name registration is void. Publication fees vary but typically run around $50. Most online sellers don’t think about this until someone asks for their DBA paperwork.
Local City or County Licenses
State registration takes care of your tax account. Your city or county may layer its own licensing on top. Illinois has a large number of home rule municipalities with broad authority to regulate businesses inside their borders, and the rules vary widely. A larger city may require a general business license for any commercial activity, while a smaller town may require nothing beyond state registration for an online seller.
If you’re working from home, check whether you need a home occupation permit or whether your residential zone allows commercial activity at all. Zoning restrictions on home-based businesses often cover inventory storage, customer visits, and exterior signage. Those rules apply even when your business is entirely online.
There is no statewide database of local licensing requirements. The only reliable way to find out what applies to you is to call your city or county clerk’s office directly. What applies in one town may not apply five miles down the road.
Do You Need an EIN?
You need a Federal Employer Identification Number if your business is an LLC, partnership, or corporation, or if you plan to hire employees. Sole proprietors can use their Social Security Number on Form REG-1, though many prefer to get an EIN to keep their SSN off business paperwork.
The IRS issues EINs for free through its online application at IRS.gov/EIN. The number comes back immediately, and the whole process takes about 15 minutes. The application must be completed in one session and times out after 15 minutes of inactivity, so have your details ready before you start. You’re limited to one EIN per responsible party per day.8Internal Revenue Service. Get an Employer Identification Number
If you’re forming an LLC or corporation, complete your entity formation through the Illinois Secretary of State before applying for the EIN. The IRS notes that applying before your entity is formed can cause delays.8Internal Revenue Service. Get an Employer Identification Number
What Registration Actually Obligates You to Do
Once registered, you charge Illinois sales tax on taxable sales and file Form ST-1, the Sales and Use Tax and E911 Surcharge Return, on the schedule the Department assigns. Filing can be monthly, quarterly, or annual, and returns are due by the 20th of the month after the reporting period.9Illinois Department of Revenue. Sales and Use Taxes New sellers with modest volume often start on a quarterly schedule. If your average monthly tax liability reaches $20,000, Illinois requires quarter-monthly payments.
The tax rate depends on where the buyer is, not where you are. Illinois uses destination-based sourcing for all retail sales, including remote sales, as of January 1, 2025.10Illinois Department of Revenue. FY 2025-10 Retailers Occupation Tax Guidance for Out-of-State Retailers The state rate is 6.25%, and local add-ons bring combined rates to somewhere between 7.25% and 11.00%.11Illinois Department of Revenue. Sales Tax Rate Change Summary Effective January 1 2026 Most e-commerce platforms and tax software look up the right rate automatically, which is worth having given how many jurisdictions Illinois contains.
Registration also lets you buy inventory tax-free with a Certificate of Resale (Form CRT-61). You give the completed certificate to your supplier, and because the goods will be resold, sales tax is collected only when your customer buys them. The certificate needs your name and address, the supplier’s information, a description of the goods, a statement that the purchase is for resale, your Illinois retailer account ID, and your signature. Suppliers are required to verify your account ID is active.12Illinois Department of Revenue. CRT-61 Certificate of Resale Instructions Using a resale certificate for goods you actually keep for business use owes tax on the purchase, and the Department pursues misuse.
What Happens If You Skip Registration
This is the part new sellers underestimate. Illinois treats sales tax as a trust tax, which means the state considers that money to belong to the government whether you collected it from customers or not. If you should have been collecting and weren’t, you owe the tax yourself.
Penalties stack. Late payment runs 2% of the unpaid tax in the first 30 days and 10% after that. Tax discovered during an audit carries a 15% penalty on any amount not paid before the audit began, rising to 20% if it’s still outstanding 30 days after the audit assessment. Failure to file triggers a separate penalty, starting at the lesser of $250 or 2% of the tax due, with a second-tier penalty of the greater of $250 or 2% (capped at $5,000) if you still haven’t filed 30 days after a nonfiling notice.13Illinois Department of Revenue. Publication 103 Penalties and Interest for Illinois Taxes
The harder edge is personal liability. Responsible individuals — the people who were supposed to file and pay — can be pursued personally for the full amount of unpaid tax, penalties, and interest. An LLC doesn’t shield you from this. The state can collect from you personally even if the business closes. Since registration itself costs nothing, there’s no upside to putting it off once you have nexus.