No. Illinois does not charge a flat 15% tax on every delivery. The Illinois Department of Revenue (IDOR) may assess tax at 15% on the gross receipts of sales subject to destination-based tax when the seller cannot provide sufficient information, schedules, or supporting documents to determine where the goods were delivered or where the buyer took possession. The rate is an assessment for undetermined locations—not the ordinary rate for a known Illinois address—and it may be used in an audit for periods before 2026 as well as for current periods.
For a delivery with a documented Illinois destination, the seller generally uses the state and local rate in effect at that destination when the sale is subject to destination-based retailers’ occupation tax (ROT). The 15% rule is not limited to remote sellers: it concerns destination-based sales with inadequate location support. Whether you must register, collect, and report Illinois tax depends on your physical presence, sales, marketplace arrangements, and applicable threshold. The exact position depends on your circumstances—confirm with IDOR, or talk to Sales Tax Compliance USA and we will check it for you.
Key takeaways
- The 15% rate is an undetermined-location assessment, not a flat tax on all Illinois deliveries.
- IDOR says the rule applies beginning January 1, 2026, and may be used in audits of earlier periods.
- For destination-based sales, use the documented Illinois delivery or possession location to determine the applicable rate.
- Keep the customer name, complete delivery address, and shipping or delivery support tied to each transaction.
- Remote-seller registration depends on the current threshold and physical presence; marketplace sales require a separate responsibility review.
What Illinois’s 15% undetermined-location tax means
Illinois calls the 15% treatment an undetermined-location assessment. For a sale subject to destination-based tax, IDOR can apply 15% to the sale’s gross receipts if the taxpayer does not provide enough information, schedules, or supporting documents to establish the proper destination. In other words, the issue is not simply that a customer’s address is in Illinois; it is that the seller cannot substantiate the location needed to determine the applicable tax.
The 15% is not a universal Illinois sales-tax rate and does not replace the ordinary destination rate for a properly documented delivery. A seller should not charge every Illinois customer 15% as a precaution. Instead, preserve the delivery details and report the sale using the rate for the established destination when destination-based tax applies. IDOR’s Publication 113-D and destination-based sales tax guidance explain the assessment and recordkeeping rule.
When the 15% assessment takes effect—and which periods it can reach
IDOR states that the 15% undetermined-location treatment applies beginning January 1, 2026. That is the start of the rule as currently described by the department; it is not a date on which all Illinois deliveries began being taxed at 15%.
IDOR has also stated that it may use the 15% undetermined-location rate during an audit for any period under audit, including reporting periods before January 2026. That makes historical records important: a seller reviewing earlier Illinois filings should not assume that an older period is outside the assessment merely because the current rule began in 2026. The treatment applies to destination-based sales whose locations cannot be adequately determined, not automatically to every sale in an audit.
Which Illinois sales are destination-based
For tangible personal property, destination-based ROT uses the state and local rates in effect at the Illinois location to which the item is shipped or delivered, or where the purchaser takes possession. IDOR describes destination-based ROT as applying to qualifying sales made by retailers that meet the applicable tax-remittance threshold or have physical presence in Illinois. The sourcing question is where the buyer receives the goods—not simply where the seller is located or where an online order is placed.
Illinois also has destination-based rules for certain transfers of tangible personal property made as part of a sale of service. Those transactions have their own sourcing and tax details, so sellers of services that transfer goods should check the applicable IDOR guidance rather than assume ordinary ecommerce rules cover them. For marketplace transactions, review Marketplace facilitator rules in Illinois to understand which party is responsible for collection and reporting.
How Illinois remote-seller thresholds work
For remote retailers selling tangible personal property, IDOR’s current guidance identifies a $100,000 cumulative gross-receipts threshold for sales to Illinois purchasers during the preceding 12-month period. The retailer checks the threshold quarterly, at the end of March, June, September, and December. Beginning in 2026, the former 200-separate-transaction threshold no longer applies to determine whether a remote retailer meets the threshold for these sales.
A remote retailer that meets the threshold is generally required to register, collect and remit applicable state and local ROT on its Illinois retail sales, and file the required returns. Physical presence can independently create Illinois obligations, so a seller should not rely on the remote-seller threshold as a safe harbor if it has an Illinois business presence or inventory. For a fuller discussion, see Economic nexus in Illinois and, for inventory stored in fulfillment facilities, Amazon FBA sales tax in Illinois.
Marketplace sales require a separate responsibility check. A marketplace facilitator may collect and remit tax on transactions it facilitates, but sellers should verify how their own direct sales, marketplace sales, registration, and returns are treated. The threshold and responsibility analysis can depend on the seller’s facts and the type of transaction; confirm the current application with IDOR or a tax professional.
What records document a delivery location
Keep records that connect each sale to the actual delivery or possession location. IDOR’s recordkeeping guidance calls for the customer’s name and billing address, the customer name and exact address where the property was shipped or delivered or possession was taken, and supporting documentation for the shipment location where applicable. For destination-based transactions, the ST-1 instructions emphasize the full name and street address for each delivery.
In practice, retain order and invoice details, the complete ship-to address, fulfillment or shipping records, and any delivery or pickup documentation that supports where the buyer received the goods. Keep records in a form that can be reconciled to the sales figures and schedules reported on Form ST-1 and, where required, Form ST-2. A billing address alone may not establish the delivery destination when the goods were shipped elsewhere.
For exempt or resale transactions, retain the relevant exemption documentation as well as the delivery evidence. See Resale and exemption certificates in Illinois for related recordkeeping considerations. IDOR’s Publication 113 explains that inadequate books and records can delay return processing and lead to an undetermined-location assessment, penalties, and interest.
How to find the rate for an Illinois delivery address
Start with the complete delivery address, including street number, street name, city, and ZIP code. Use IDOR’s official destination-based sales tax rate lookup or its destination-based sales tax assistance resources to identify the applicable state and local rate for that address and the relevant transaction date. Rates can vary by destination, so a city name or ZIP code alone may not be enough to support the location used on a return.
Save the address and rate determination with the transaction records, and check the rate applicable to the sale date rather than assuming a rate remains unchanged. If the address is incomplete, the lookup produces an uncertain result, or the transaction has unusual delivery or pickup facts, do not substitute a guessed rate. The exact position depends on your circumstances—confirm with IDOR, or talk to us and we will check it for you.
Registration and reporting destination-based sales
Register with IDOR when your business has an Illinois physical presence or meets the applicable tax-remittance threshold, subject to the rules for your business and transactions. A remote seller below the threshold may not have the same collection obligation as a seller that meets it, but physical presence and other facts can change the result. Marketplace collection does not automatically answer every question about a seller’s own registration or direct sales.
For destination-based transactions that you are responsible for reporting, include the sales on the applicable Illinois return, Form ST-1, and report local destination information through Form ST-2 where required. IDOR’s instructions require destination-based transactions to be supported by the full delivery name and street address; the return schedules must support the reported figures and locations. Follow the current form instructions for the reporting period, since filing requirements and form details can change.
If you have missed registration or filings, do not assume that simply starting to collect tax resolves earlier exposure. Review Back sales tax and penalties in Illinois and Can Illinois sellers use the 2026 remote-retailer amnesty? for related issues, then confirm eligibility and next steps with IDOR or an adviser.
Avoiding assessments and understanding additional penalties
Build location capture into order processing: require a complete ship-to address, preserve the address as it appeared when the order was fulfilled, and retain shipping or delivery evidence that can be matched to the sale. Reconcile those records to the destination rates and local schedules used on returns. For marketplace orders, retain the transaction and facilitator records needed to distinguish marketplace-collected tax from sales for which your business remains responsible.
Yes, an undocumented location can lead to more than the 15% assessment. IDOR states that undetermined-location tax may be subject to penalties and interest, and that additional penalties may also be assessed. Its recordkeeping publication also describes a penalty for failure to keep required books and records. The amount and application depend on the facts and the specific legal basis, so this article does not estimate a total liability.
If records are incomplete, preserve what remains and identify which transactions lack support before filing or responding to an inquiry. Do not invent delivery addresses or use a blanket rate to fill gaps. A review of the transaction data, return history, and available shipping evidence can help determine the appropriate response; Sales Tax Compliance USA provides done-for-you sales tax compliance support and can review the facts with you.
Not sure how this applies to your business? We handle US sales tax registration, filing and remittance for ecommerce sellers as a fully managed service, for one fee. Book a free consultation and we will review your own position with you.
How Illinois destination-based tax treatment differs by transaction situation
| Situation | How location is determined | Potential tax treatment | Records to retain |
|---|---|---|---|
| Documented shipment to an Illinois customer | The Illinois address where the item is shipped or delivered | Use the destination state and local rate when destination-based ROT applies | Customer and full ship-to address, order or invoice, and shipping or delivery evidence |
| Buyer takes possession in Illinois | The Illinois location where the purchaser takes possession | Destination rate may apply based on the possession location | Pickup or transfer record identifying the buyer, date, and exact location |
| Destination-based sale with insufficient location support | Location cannot be established from the information and supporting records provided | IDOR may assess 15% on gross receipts assigned to undetermined locations; penalties and interest may also apply | Reconstruct and preserve available order, address, fulfillment, and delivery records; do not guess |
| Remote retailer below the applicable threshold, with no Illinois physical presence | Threshold and presence analysis determines whether the retailer has a collection obligation | The 15% rule is not a general rate for all such deliveries; confirm whether registration and collection are required | Illinois sales totals by relevant period, transaction records, and evidence concerning physical presence |
| Sale through a marketplace facilitator | Destination is still relevant to destination-based sourcing; collection responsibility depends on marketplace rules | Check facilitator collection and the seller’s separate filing and registration obligations | Marketplace transaction statements, tax collected records, order destination, and direct-sales records |
Frequently asked questions
What is Illinois’s 15% undetermined-location tax?
It is an IDOR assessment rate for gross receipts from destination-based sales when the taxpayer cannot provide sufficient information and supporting records to determine the proper location. It is not the ordinary rate for every Illinois delivery. The sale may also be subject to penalties and interest, depending on the circumstances.
When does Illinois’s 15% sales-tax rate take effect?
IDOR states that the rule applies beginning January 1, 2026. The department has also said it may use the rate in an audit for any period under audit, including periods before January 2026, when the location of destination-based sales cannot be adequately established.
Does Illinois charge a flat 15% tax on all deliveries?
No. A documented destination is generally taxed using the applicable state and local rate for that location when destination-based tax applies. The 15% rate is for gross receipts assigned to undetermined locations because the seller lacks sufficient location information or support.
Does the 15% rate apply to remote sellers?
It can apply to destination-based sales made by a remote seller if the seller has a collection and reporting obligation and cannot substantiate the sale location. It is not a special flat rate imposed on every remote seller or every remote sale. Registration and collection obligations depend on the seller’s threshold, physical presence, and transaction facts.
Which Illinois sales are subject to destination-based sales tax?
Qualifying retail sales of tangible personal property by retailers subject to Illinois ROT rules are generally sourced to the Illinois location where the goods are shipped or delivered, or where the purchaser takes possession. Certain transfers of tangible personal property as part of a sale of service also have destination-based rules. Check IDOR guidance for the specific transaction type.
What information must sellers keep to document a delivery location?
Keep the customer’s name and billing address, the customer name and exact delivery or possession address, and records supporting shipment or delivery. IDOR’s instructions call for the full name and street address for each destination-based delivery. Retain records that reconcile to the sales and schedules on your Illinois returns.
How do I find the Illinois sales-tax rate for a delivery address?
Use IDOR’s official destination-based rate lookup or assistance resources with the complete street address and the relevant sale date. Preserve the address and rate determination with the transaction records. If the address or result is uncertain, confirm it with IDOR or a tax professional rather than guessing.
Can Illinois assess additional penalties when a sale’s location is undocumented?
Yes. IDOR says the undetermined-location tax may be subject to penalties and interest, and additional penalties may also be assessed. Failure to keep required books and records can carry a separate recordkeeping penalty; the outcome depends on the facts and applicable rules.
Official sources
- https://tax.illinois.gov/research/taxinformation/sales/destination-based-sales-tax-assistance.html
- https://tax.illinois.gov/research/publications/pubs/overview-of-destination-based-sales-tax.html
- https://tax.illinois.gov/research/publications/pubs/retailers-overview-of-sales-and-use-tax/keeping-complete-and-accurate-records.html
- https://tax.illinois.gov/research/taxinformation/sales/rot.html
- https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/sales/documents/sales/st-1-instr.pdf
- https://tax.illinois.gov/research/publications/bulletins/fy-2026-28.html
Related reading
- Amazon Fba Sales Tax in Illinois
- Back sales tax and penalties in Illinois
- Can illinois sellers use the 2026 remote-retailer amnesty?
- Economic nexus in Illinois
- Our sales tax compliance services
Getting this handled
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Reviewed by Paul le Roux, CA(SA). Sales Tax Compliance USA handles US sales tax registration, filing and remittance for cross-border and domestic ecommerce sellers as a fully managed service.
This article is general information for educational purposes and does not constitute legal or tax advice. Sales tax rules change and depend on your specific facts. Consult a qualified tax professional about your own position.