How to Fill Out Illinois Form ST-1: Receipts, Tax, and Filing

To fill out Illinois Form ST-1, enter your gross receipts on Line 1, subtract the deductions you calculate on Schedule A, split the net receipts into general merchandise, qualifying drugs and medical appliances, and qualifying groceries at their separate rates in Step 3, add any E911 surcharge from Schedule B, subtract the 1.75% vendor’s discount for filing on time, and submit through MyTax Illinois by the 20th of the month after the reporting period ends.1Illinois Department of Revenue. ST-1 Instructions

What to Have in Front of You

The return moves quickly once you have the numbers. Pull these together first:

  • Your Illinois Business Tax (IBT) number from your Certificate of Registration.2Illinois Department of Revenue. Business Registration
  • Your Federal Employer Identification Number.
  • Gross receipts for the reporting period, including every sale, lease, rental, service charge, tax collected, E911 surcharge, and ITAC assessment.
  • Receipts broken out by category: general merchandise, qualifying drugs and medical appliances, and qualifying groceries. The rates differ, so mixed totals will not work.3Illinois General Assembly. Illinois Administrative Code 86 Part 130.311 – Drugs, Medicines, Medical Appliances, and Grooming and Hygiene Products
  • Valid exemption certificates on file for every deduction you plan to claim on Schedule A. Without the paperwork, the deduction does not stand.
  • Alcoholic liquor purchase records (the total dollar amount invoiced and delivered during the period), if you sell alcohol and are not on the quarter-monthly schedule.
  • Motor fuel sales records, if applicable.

If you operate from more than one location, each site’s numbers go on Form ST-2, and the combined figures flow onto a single ST-1.

Sort Your Receipts by Category First

Category assignment is the step that trips people up. Three rates are in play on the ST-1:

“Groceries” here means food for human consumption eaten off the premises. Alcoholic beverages, soft drinks, candy, cannabis-infused food, and food prepared for immediate consumption are not qualifying groceries and stay at the general merchandise rate. If you sell both ready-to-eat food and take-home groceries, keep the two separated in your records. Businesses that cannot show the split get taxed on all food sales at the higher rate.

Working Through the Form

Step 1: Alcoholic Liquor and Motor Fuel

Line A takes the total dollar amount of alcoholic liquor invoiced and delivered during the reporting period. Line B takes your total taxable motor fuel receipts. Leave both blank if neither applies.

Step 2: Figure Your Taxable Receipts

Line 1 is your gross receipts from every sale, lease, and rental during the period, including all taxes collected, service charges, E911 surcharges, and the ITAC assessment. Report the full amount received. Do not subtract anything at this stage.

Line 2 is the total of your deductions. Flip the form over and complete Schedule A first. Schedule A is where sales to tax-exempt organizations, sales for resale with a valid certificate, and returned merchandise get itemized. Carry the total from Schedule A, Line 32 back to Line 2. Line 3 is Line 1 minus Line 2, and it is the net taxable figure you carry into Step 3.

Step 3: Tax on Receipts

Split the Line 3 total into categories and apply the correct rate to each:

  • Lines 4a and 4b: general merchandise.
  • Lines 5a and 5b: qualifying drugs and medical appliances at 1%.
  • Lines 5c and 5d: qualifying grocery items. Relevant if your locality still imposes a grocery tax or you sell within the RTA or MED regions.

Additional lines in Step 3 cover use tax on items your business bought for its own use in Illinois. If you purchased general merchandise or qualifying items from out-of-state sellers who did not collect Illinois tax, report those amounts on the corresponding use-tax lines.

Schedule B: E911 Surcharge

If you sell prepaid wireless telecommunications service, calculate the E911 surcharge on Schedule B. The rate depends on whether the sale occurred at a Chicago or non-Chicago location. Look up the current rate for your location in IDOR’s Tax Rate Database before filling in Schedule B.5Illinois Department of Revenue. Prepaid Wireless E911 Surcharge The calculated surcharge carries over to the main return.

Vendor’s Discount

File and pay on time and you keep 1.75% of the tax you collected. You calculate the discount right on the ST-1. File late and the discount is gone for that period. There is no partial credit for being a few days off.

Submitting the Return

Most filers use MyTax Illinois at mytax.illinois.gov.6Illinois Department of Revenue. Sales and Use Tax Forms Log in, open your sales tax account, and enter your figures into the online version of the form. The system runs the calculations as you go, which catches arithmetic errors before you submit. Once you review and file, save the confirmation number as proof.

You can pay electronically at the same time. Electronic payment is mandatory if you are enrolled in the Electronic Funds Transfer program, and enrollment is required once your annual tax liability reaches $20,000.7Illinois Department of Revenue. Sales and Use Taxes

Paper filing is still allowed. Download the current form, complete it by hand, and mail it with a check or money order to:

Illinois Department of Revenue
Retailers’ Occupation Tax
Springfield, IL 62736-0001

The postmark counts as your filing date, so mailing on the 20th is timely. Paper returns take longer to process and give you no instant confirmation.

When It Is Due

The ST-1 is due by the 20th of the month following the end of the reporting period. IDOR sets your filing frequency based on your liability history:

  • Monthly if your average monthly liability is more than $200.
  • Quarterly if it is between $50 and $200.
  • Annual if it is less than $50.

If your average monthly liability reaches $20,000, you also owe quarter-monthly (accelerated) payments on the 7th, 15th, 22nd, and last day of each month. The ST-1 return itself still follows the normal monthly schedule; the extra dates are payment deadlines only.

Late filing or late payment triggers tiered penalties plus daily interest at the federal underpayment rate under IRC Section 6621, updated each January 1 and July 1.8Illinois Department of Revenue. Pub-103, Penalties and Interest for Illinois Taxes

If You Find a Mistake After Filing

File Form ST-1-X, one per reporting period you want to correct.9Illinois Department of Revenue. ST-1-X Instructions If you originally filed through MyTax Illinois, amend electronically for the same period and pay any additional tax through the portal. Paper filers mail the ST-1-X to the same Springfield address. Multi-site filers who used Form ST-2 must file ST-2-X for each location that changed; on paper, submit ST-2-X only for the locations with actual changes.

There is no deadline for paying additional tax on an amended return, but interest and penalties keep accruing until you do. If you overpaid and want a credit, timing matters: filing between January 1 and June 30 lets you claim overpayments made in the current year and the prior 36 months; filing between July 1 and December 31 shortens the lookback to 30 months.