Sales Tax Nexus in Illinois: What Online Sellers Need to Know

The Short Answer

Illinois triggers a sales tax obligation once you hit $100,000 in annual gross receipts from Illinois sales. The 200-transaction threshold was eliminated effective January 1, 2026, so only the dollar threshold applies now. Marketplace-facilitated sales don't count toward your threshold — and Illinois completed a major structural overhaul in 2025 that moved remote sellers to destination-based tax rates.

Economic Nexus Threshold

• Dollar threshold: $100,000 in cumulative gross receipts from tangible personal property sales into Illinois
• Transaction threshold: None — eliminated effective January 1, 2026 (was previously 200 transactions)
• Measurement period: Preceding 12-month period, assessed quarterly (quarterly check dates: last day of March, June, September, December)
• Effective date: Original remote seller provisions October 1, 2018; destination-based ROT for remote sellers effective January 1, 2025

Important 2025 change: Illinois moved remote sellers from a Use Tax system to destination-based Retailers' Occupation Tax (ROT). If you registered before 2025, your filing structure changed. Same rate, different form.

Does Illinois Count Marketplace Sales Toward Your Threshold?

No. Marketplace-facilitated sales are excluded from the remote seller's own $100,000 threshold. Only your direct sales (Shopify, your own website, etc.) count.

The marketplace facilitator itself has separate obligations — they must collect and remit Illinois destination-based ROT on all their facilitated sales. Amazon, Etsy, eBay, and other major platforms handle this automatically.

What Taxable Products Look Like in Illinois

Illinois rates vary from the state rate up to significantly higher combined totals in Chicago with all local additions — check the Illinois Department of Revenue's rate lookup for your buyer's exact location.

• Clothing: Taxable at the full rate
• Groceries/Food: As of January 1, 2026, the state grocery tax was eliminated (P.A. 103-0781). However, individual municipalities can now opt to impose their own local grocery tax — so the effective rate on groceries varies by city.
• Digital goods and SaaS: Illinois generally does not broadly tax SaaS services. Remotely accessed software is typically treated as a non-taxable service. Electronically downloaded software may be taxable.
• Rate calculation: Illinois is destination-based as of 2025. The rate is determined by where your buyer receives the product.

How to Register in Illinois

Illinois is not an SST member. Register via MyTax Illinois:

• Portal: mytax.illinois.gov
• Cost: Free
• Timeline: A few business days
• Form: File Form ST-1 for sales and use tax returns

MyTax Illinois is generally clean for registration — no significant CAPTCHA issues.

Filing Requirements

Illinois assigns frequency based on your liability level:

• Monthly: Larger filers
• Quarterly: Standard for most remote sellers
• Annual: Small filers

Due date: 20th of the month following the reporting period. File Form ST-1 electronically via MyTax Illinois.

Note: If you're filing for the first time after the 2025 destination-based ROT change, you'll use Form ST-1 (not the old CT forms some prior-registered sellers may have used).

What Happens If You Don't Register

Illinois penalty structure:

• Late payment penalty: 2% per month on unpaid tax
• Interest: Applies on top of penalties

Illinois has a voluntary disclosure program — contact IDOR if you have past-period exposure you'd like to resolve.

How Taxero Handles Illinois

Illinois's 2025 structural change — moving remote sellers from Use Tax to destination-based ROT — is the kind of behind-the-scenes change that trips sellers up if they're not paying attention. Taxero tracks your Illinois direct sales, notifies you when you approach $100,000, and handles registration and ongoing filings using the updated destination-based ROT system. We also track the municipal grocery tax landscape so your product tax classifications stay accurate if you sell food products.

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