Illinois Sales Tax Nexus Thresholds — 2026
Last updated: April 2026
Researched by the NexusFlag Research Team
Illinois requires remote sellers to collect and remit sales tax once they exceed EITHER $100,000 in annual gross revenue OR 200 transactions with Illinois customers within a calendar year.
Source: Illinois Department of RevenueIllinois Nexus Threshold Details
Annual gross sales to in-state customers
Number of separate taxable transactions
Nexus triggers when EITHER threshold is crossed first
How sales into the state are counted
Whether Amazon/marketplace sales count toward threshold
Year the economic nexus law took effect
How quickly you must register after nexus is triggered
How often returns are typically due at low volume
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Frequently asked questions about Illinois sales tax nexus
When does economic nexus trigger in Illinois?
Illinois economic nexus triggers when a remote seller exceeds $100,000 in revenue or 200 transactions from Illinois customers within a calendar year. Once triggered, the seller must register with the Illinois Department of Revenue and begin collecting and remitting sales tax.
How long do I have to register after crossing nexus in Illinois?
Illinois requires sellers to register within 30 days of crossing the economic nexus threshold. Failing to register on time may result in back taxes, interest, and penalties assessed by the Illinois Department of Revenue.
Do marketplace sales count toward Illinois's nexus threshold?
Illinois generally excludes marketplace-facilitated sales from the economic nexus threshold calculation, because the marketplace is responsible for collecting and remitting tax on those sales. Only direct sales from your own channels count toward the Illinois threshold.
How often do I need to file sales tax returns in Illinois?
Illinois assigns filing frequency based on your sales volume. New remote sellers typically start on monthly filing. Illinois may adjust your frequency over time as your Illinois sales volume becomes clearer. Check with the Illinois Department of Revenue for your assigned frequency after you register.
Disclaimer: NexusFlag provides informational data about published state nexus thresholds — not tax advice. State laws change frequently. Always verify current Illinois threshold requirements with the Illinois Department of Revenue or a qualified sales tax professional before making compliance decisions.