Illinois Sales Tax Registration: How to Register on MyTax Illinois

If you're selling taxable goods or services in Illinois, you need an Illinois sales tax ID before you can legally operate. The good news: registration is free, takes 1 to 2 business days online, and happens through a single straightforward process. This guide walks you through registering for an Illinois sales tax permit using MyTax Illinois, understanding your filing obligations, and getting your Certificate of Registration.

What You Get: The Certificate of Registration

When you complete Illinois sales tax registration through MyTax Illinois, you receive a Certificate of Registration. This is not called a "sellers permit" in Illinois, though it serves the same function. The certificate is your official proof that you are registered with the Illinois Department of Revenue (IDOR) to collect and remit sales tax.

The Certificate of Registration:

• Covers both sales tax collection and employee withholding obligations
• Must be displayed at your place of business where customers can see it
• Is issued free of charge
• Gives you an Illinois sales tax ID number (also called your Illinois state tax ID) that you'll use on every sales tax return
• Is not a substitute for a local business license or other permits your city or county may require

Illinois issues no single statewide business license. The Certificate of Registration handles your state-level sales tax obligation only. You may still need separate licenses from your municipality, county, or industry regulator, but the sales tax ID comes purely from the state.

Who Must Register for Illinois Sales Tax

You must register for an Illinois sales tax ID if you:

• Sell tangible personal property (physical goods) in Illinois, even if you're based outside the state
• Provide services subject to Illinois sales tax (some services are taxable, others are not)
• Have employees working in Illinois and must withhold state income tax
• Are a marketplace facilitator or online seller using a platform like Amazon, eBay, or Shopify

Illinois sales tax applies to most tangible goods at a base rate of 6.25 percent, though local jurisdictions add additional tax on top. Your actual tax rate depends on your business location.

If you make sales into Illinois from outside the state with no physical presence here, you must register once you meet IDOR's remote retailer threshold: $100,000 or more in Illinois gross receipts, or 200 or more separate transactions, as IDOR currently lists it. Check IDOR for the current thresholds.

How to Register: Step-by-Step

Option 1: Register Online (Recommended - Fastest)

Registering online through MyTax Illinois is the quickest route. You'll get your Illinois tax ID number in 1 to 2 business days.

Step 1: Go to the IDOR registration page. Visit https://tax.illinois.gov/businesses/registration.html and follow the link to register through MyTax Illinois. You can also access MyTax Illinois directly.

Step 2: Create or log into your MyTax Illinois account. If this is your first time, you'll set up a new account. Have your Social Security Number or Federal Employer Identification Number (EIN) ready.

Step 3: Complete the online registration form. You'll be asked for:

• Business name and legal structure (sole proprietorship, LLC, corporation, partnership, etc.)
• Business location and mailing address
• Owner and manager names and SSNs or EINs
• Description of business activities (what you sell or do)
• Expected monthly sales or revenue
• Start date of your business or the date you began making sales

Step 4: Submit and receive confirmation. After you submit the online form, IDOR will process it within 1 to 2 business days. You'll receive an email confirmation with your Illinois sales tax ID and instructions for printing or accessing your Certificate of Registration.

Option 2: Register by Mail (Slower)

You can also register using Form REG-1, the paper application for sales tax registration. Download it from the IDOR website, fill it out by hand or typewriter, and mail it to the Illinois Department of Revenue.

Processing time by mail is 4 to 6 weeks. For this reason, most businesses prefer the online route.

Understanding Form REG-1

Form REG-1 is the Illinois business tax registration form that covers sales tax, withholding tax, and other state tax obligations. Whether you register online or by mail, you're completing the same registration process; the online version is just the digital equivalent.

If you register online, you don't need to print and mail Form REG-1. MyTax Illinois handles the data entry for you. If you prefer to register by mail, download Form REG-1 from https://tax.illinois.gov, fill in your business details, and mail it to the address shown on the form.

You may see Reg-1 Illinois or Illinois Reg-1 references online; these simply refer to this standard registration form and process.

Processing Times and What to Expect

Online registration: 1 to 2 business days. This is counted from the day you submit. If you submit on a Friday evening, the clock often starts Monday morning.

Paper mail registration: 4 to 6 weeks. This is why registering through MyTax Illinois is strongly recommended, especially if you want to start accepting sales quickly.

Once your registration is approved, IDOR will send you your Certificate of Registration. For online registrations, you can typically access and print this certificate immediately from your MyTax Illinois account. For mail registrations, a physical copy will be mailed to you.

You should not begin collecting sales tax until you have received your registration confirmation and sales tax ID. Collecting sales tax without proper registration can result in penalties and back taxes owed.

Your Illinois Sales Tax Filing Obligations

After you receive your Illinois sales tax ID, you must file sales tax returns on a regular schedule. Your filing frequency depends on your average monthly sales tax liability:

• Monthly filers: If your average monthly tax liability exceeds $200, you file monthly. Returns are due on the 20th of the following month.
• Quarterly filers: If your average monthly tax liability is $200 or less, you file quarterly. Returns are due by the 20th of the month following the end of each quarter.
• Annual filers: If your average monthly tax liability is $50 or less, you may file annually. Returns are due by the 20th of the month following the close of the year.
• Quarter-monthly payers: If your average monthly tax liability is $20,000 or more, you still file monthly returns but must make quarter-monthly payments on dates set by IDOR.

When you register, IDOR assigns you a filing frequency based on your estimated sales. You can request a different frequency if your actual liability changes.

Illinois sales tax filing uses Form ST-1, the Sales and Use Tax and E911 Surcharge Return. You file this form through MyTax Illinois or by mail. The form shows the gross receipts from your sales and calculates the tax you owe. You then remit payment along with the return.

Mark these dates on your calendar: Sales tax returns are due on the 20th of the month following the filing period. Missing this Illinois sales tax due date results in penalties and interest. If the 20th falls on a weekend or holiday, the deadline moves to the next business day.

After Registration: Next Steps

Display your Certificate of Registration. By law, the Certificate must be posted at your place of business where customers can see it. This shows that you're registered and operating legally.

Set up recordkeeping. From day one, keep detailed records of all sales, including sales tax collected. IDOR can audit your business and will want to see receipts, invoices, and tax returns going back several years. Use accounting software or a simple spreadsheet to track gross sales and tax collected by month.

Understand local sales tax. The 6.25 percent Illinois sales tax rate is just the state portion. Your city and county add their own local sales taxes on top. The total rate at the register may be 7 or 8 percent, and in Chicago it is 10.5 percent from August 1, 2026, depending on where your business is located. The MyTax Illinois Tax Rate Finder shows the combined rate for your address, and this is what you charge customers.

Keep your registration current. If you move your business, change your business name, add a second location, or make other significant changes, notify IDOR promptly. You can update your registration through MyTax Illinois or by contacting the department directly.

Set aside the sales tax you collect. Whether you're a quarterly or monthly filer, set aside money each week to cover your sales tax liability. Many business owners underestimate how much they owe because they forget that sales tax is not income for the business; it's money held in trust for the state. Spend it, and you'll face penalties and interest when the bill comes due.

Common Questions About Illinois Sales Tax Registration

Do I need a separate Illinois sellers permit? No. Illinois calls it a Certificate of Registration, not a sellers permit. Some states use the term "sellers permit," but in Illinois, the Certificate of Registration serves that function.

Is there a fee to register? No, Illinois sales tax registration is completely free. There is no charge to obtain your Illinois sales tax permit or Certificate of Registration.

What if I'm a sole proprietor without an EIN? You can register using your Social Security Number. You do not need an EIN to register for sales tax, though having one is recommended if you have employees or want to keep your business and personal finances separate.

Can I register before my business opens? Yes. You can register as soon as you know you'll be making sales in Illinois. Some business owners register after forming an LLC or corporation but before they open for business. This lets you have everything in place on day one.

How long does my registration last? Your registration does not expire. It remains active as long as you continue to file returns on time and keep your information up to date. If you stop doing business in Illinois and want to close your registration, notify IDOR.

Will I owe back sales tax if I didn't register right away? Possibly. If you've been collecting sales without being registered, IDOR may assess back taxes, penalties, and interest when they discover the violation. Registering now is the best way to bring yourself into compliance and avoid larger problems down the road.

Where to Get Help

For detailed information on Illinois business tax registration, visit the Illinois Department of Revenue at https://tax.illinois.gov/. Their Businesses section has forms, instructions, and contact information.

You can also call IDOR or use the live chat on their website if you have questions about your specific situation.

For local sales tax rates, use the MyTax Illinois Tax Rate Finder. For local licenses or registrations, contact your city or village clerk, or the county for unincorporated areas.

Disclaimer

This guide is informational content only and is not legal or tax advice. Sales tax law is complex and can vary based on your specific business type, location, and activities. Before registering, consult a qualified accountant or attorney who is familiar with Illinois tax law and your industry. They can review your situation and make sure you register correctly and understand all your obligations.

The figures, deadlines, and procedures described here reflect Illinois Department of Revenue guidance. Tax law changes periodically. Always verify current requirements directly with IDOR before taking action.