Filing your Illinois sales tax return is simple with the state’s online system. You can file and pay directly through MyTax Illinois, as long as your business is registered to collect and remit sales tax.
This guide will walk you through the step-by-step process of filing online so you can submit returns on time, avoid penalties, and stay compliant with Illinois’s sales tax rules.
What You Need Before Filing
Before filing your sales tax return, you must prepare specific records to ensure your report is accurate. Here are the standard documents required to file a sales tax return in Illinois:
- Illinois Taxpayer Account Number (Sales Tax Permit) – You’re required to provide your Illinois sales and use tax account number to file your sales tax return. Once your registration with the Illinois Department of Revenue is approved, you should receive this documentation via mail. This number is your official business tax identification number with the IDOR. This number can be found on your Illinois Sales Tax Permit document.
- My Tax Illinois eServices Account Log-in Details – The primary way to file your Illinois sales tax return online is by logging onto your MyTax Illinois account. To access the site, ensure you have your log-in credentials ready (e.g., your username and password).
- Total Sales and Taxable Sales Data – Businesses must gather and report their total gross receipts for the filing period on Form ST-1, Line 1. This figure must include all revenue, regardless of whether it is taxable or not, including receipts from sales, leases, and rentals of merchandise and services. It also includes service charges, E911 Surcharge, and all state and local taxes collected. Even in periods with no sales, a return must still be filed. Businesses must also have a precise record of their taxable sales, which will be reported separately on the return.
- Gathering Taxable Purchases Records – In addition to reporting sales, businesses must also verify the total amount of taxable purchases made during the reporting period. This is crucial for correctly reporting use tax and applies to both in-state and out-of-state transactions.
- Managing Multiple Locations and Local Sales Tax Reporting – Businesses with more than one sales location in Illinois are required to file the Multiple Site Form (Form ST-2) as an attachment to their main ST-1 return. It is important to register all locations before filing to ensure the correct local tax rates are applied.
- Bank Account and Routing Number – Select which bank account you want to use for paying the due taxes in your report. Prepare your bank details and routing number ahead of time. This is required for electronic payments through MyTax Illinois.
- Filing Frequency Schedule – The state assigns a specific due date for every registered business. To find out your designated schedule, you can check your Illinois Sales Tax Permit document. This filing frequency (monthly, quarterly, or annually) is determined by the Illinois Department of Revenue based on your average monthly tax liability.
Step-by-Step: How to File Illinois Sales Tax Online
Electronic filing through the MyTax Illinois portal is the most efficient and recommended method. The process is straightforward, but attention to detail is essential. Step 1. Go to the MyTax Illinois website. Step 2. Enter your Account Credentials: Log in using your username and password. Check your shared email/phone number and input OTP, when applicable.
Step 3. Collect your Ecommerce Sales Tax Data (e.g., Taxes Report from Shopify).
Step 4. On the dashboard, scroll down to the Sales Tax section and click File a Return.
Step 5. Select the filing period you want to process, then click File Now.
Step 6. During the return process, choose the appropriate options based on your filing details.
Step 7. Enter the gross sales and any applicable deductions for each location, using your Ecommerce Sales Tax Report as a reference. Repeat this for all sites listed in your report, then click Next.
Step 8. Carefully review the entered data and compare it with your Ecommerce Sales Tax Report to ensure the figures match. Once verified, click Next.
Step 9. Enable the Retailer’s Discount option, then click Next.
Step 10. Authorize the submission and payment by entering contact information. Select Next.
Step 11. Confirm your submission by entering your account password.
Step 12. Click Proceed to Payment to continue.
Step 13. Select your preferred payment method from the available options.
Step 14. Enter your payment information and any other required details, then click Submit.
Step 15. Re-enter your password to finalize and confirm the payment, then click OK.
Step 16. Save the confirmation in your preferred location for recordkeeping purposes. Keeping online records using Google Drive is a common option.
Helpful tip: If the filing process is interrupted by internet issues, website downtime, or other disruptions. You can always click on “Save and Submit Later” to avoid losing your progress.
Due Dates
The filing frequency with which a business must file its sales tax returns in Illinois is not uniform. The IDOR determines the system based on the business’s average monthly tax liability.
Businesses need to stay aware of their liability to ensure they are filing on the correct schedule. The IDOR assigns the filing schedule based on the following criteria:| FREQUENCY | REQUIREMENT | REPORTING PERIOD | DUE DATE |
| Monthly | Greater than $200 average monthly liability | Monthly | The 20th day of the month following the reporting period |
| Quarterly | $50 – $200 average monthly liability |
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| Annually | Less than $50 average monthly liability | January 1 – December 31 | January 20 |
| Quarter-Monthly Filing | Average monthly liability of $20,000 or more | Monthly | 7th, 15th, 22nd, and the last day of the month |
Timely Filing Discount
Illinois offers a retailer’s discount to businesses that file their sales tax returns and remit payment on or before the due date. This discount serves as an incentive for timely compliance. However, a significant change effective for returns due on or after January 1, 2025 has introduced a cap on this benefit. The discount amount now has a maximum limit of $1,000 per month for each eligible periodic return. This cap applies universally, affecting monthly, quarterly, and annual filers. For small businesses, the discount often remains below the cap, offering straightforward savings. Larger companies with higher tax liabilities, however, will no longer receive the full proportional benefit.Filing Amended Returns
If your business discovers an error on a previously filed Form ST-1, you must file an amended return to correct the mistake. You can use this to either pay more tax than you originally owed or request a credit for an overpayment. You must file a separate Form ST-1-X for each reporting period that needs correction. Businesses with multiple sites that originally filed Form ST-2 must also file the companion Form ST-2-X to amend their site-specific data.Filing Zero Returns in Illinois
A business that registers for a sales tax permit in Illinois must file a return for every reporting period, even if it made no sales. Failing to file a “zero return” when no sales occur counts as non-compliance and can lead to penalties. This policy ensures that the state has a complete and accurate record of all registered businesses’ tax activities, preventing nonfiling from being used as a method of evasion.Other Filing Methods in Illinois
If you’re having difficulties filing your Illinois sales tax return online, you can try other filing options:- File with TaxHero – Let expert accountants in TaxHero prepare your sales tax returns for you. We’ll take everything off your hands so that you can spend your time more efficiently managing your business.
- File by mail – Fill up Form ST-1 and file and pay through the mail. Note: Electronic filing is mandatory for all taxpayers who have an average monthly tax liability of $5,000 or more.
- File through a Third-Party Software Vendor – File through approved third-party software vendors that integrate with the IDOR system.