GST and Sales Tax Filing Compared: Illinois Retailers' Occupation Tax, Canada GST/HST and India GST

GST vs sales tax filing is a common cross-border puzzle: Illinois taxes retail sales through the retailers' occupation tax, Canada collects GST or HST at each stage of the supply chain with input tax credits, and India runs a similar multi-stage GST with monthly and quarterly returns. The three systems differ on who registers, how often you file, and what gets reported. This page compares them for the 2026 and early 2027 calendar so a seller with customers in more than one country knows what to expect.

How do GST vs sales tax filing rules compare?

What does Illinois require?

Illinois imposes the retailers' occupation tax on sellers and a use tax on buyers, and together these are the state's "sales tax." The state rate is 6.25% (1% for qualifying drugs and medical appliances), local taxes can add to it, and the rate for a sale depends on the location: use the Tax Rate Finder in MyTax Illinois. For sales to Illinois customers from outside the state since January 1, 2025, the retailer collects destination-based retailers' occupation tax at the rate for the delivery location.

Register with Form REG-1, then file Form ST-1 electronically. IDOR sets frequency from average monthly liability: more than $200 may be monthly, $50 to $200 quarterly, and under $50 annual. Monthly returns are due on the 20th of the following month, quarterly returns on the 20th of the month after the quarter, and annual returns on January 20. When the 20th is a weekend or holiday, the next business day applies. Retailers who file and pay on time electronically earn a discount. Records must be kept for three and one-half years after filing, and failing to keep them carries a $1,000 first-failure penalty. IDOR also runs a 2026 Remote Retailer Tax Amnesty until October 31, 2026, which waives penalties and interest on eligible past sales tax; see the Illinois compliance calendar and our Illinois sales and use tax guide.

What does Canada require?

You must register for GST/HST once you exceed the $30,000 small supplier threshold in a single calendar quarter or over four consecutive quarters. Rates depend on place of supply: 5% GST in Alberta, British Columbia, Manitoba, Saskatchewan, Quebec and the territories; 13% HST in Ontario; 14% in Nova Scotia since April 1, 2025; and 15% in New Brunswick, Newfoundland and Labrador and Prince Edward Island. British Columbia, Manitoba and Saskatchewan add provincial sales tax of 7%, 7% and 6%, and Quebec adds 9.975% QST under its own rules.

Monthly and quarterly filers file and pay one month after the period, for example August 31 for July. Annual filers file three months after fiscal year-end, with a special case for sole proprietors with a December 31 year-end: payment April 30 and filing June 15. All registrants, except charities and certain financial institutions, must file electronically for periods ending in 2024 or later, with a penalty of $100 the first time and $250 after. A late-filing penalty on an amount owing is 1% of the amount plus 25% of that for each full month late, to 12 months. A return is required even with no sales. Read the Canadian GST/HST guide.

What does India require?

GST applies to supplies of goods and services at central and state levels. Under section 22 of the Central GST Act a supplier is liable to register when aggregate turnover exceeds Rs 20 lakh in a financial year (Rs 10 lakh in special category states), and a state can raise the figure up to Rs 40 lakh for suppliers exclusively of goods. The GST Portal's FAQs set the main dates:

• GSTR-1: the 11th of the next month for monthly filers and the 13th of the month after the quarter for quarterly filers.
• GSTR-3B: the 20th of the next month for monthly filers; the 22nd or 24th of the month after the quarter for quarterly filers, depending on the state.
• QRMP scheme: taxpayers with aggregate turnover up to Rs 5 crore may file quarterly and pay tax monthly; an optional invoice furnishing facility has a 13th-of-the-month cut-off.
• GSTR-9 annual return: December 31 of the following financial year, unless extended.
• Nil returns: GSTR-3B is mandatory even with no business activity.
• Records: retained until 72 months after the due date of the annual return.

Notifications can extend dates and change rates, so your Chartered Accountant confirms the current position. See GST registration and returns in India.

What are the next due dates in each country?

What steps do cross-border sellers follow?

1. Map where your customers are and where you have a physical presence or stock.
2. Check each threshold: Illinois nexus and the $100,000 reference for remote sellers, Canada's $30,000 limit, India's state turnover limit.
3. Register and get logins in each system: MyTax Illinois, CRA My Business Account, the GST Portal.
4. Choose the filing frequency you are assigned or may elect.
5. Reconcile sales per books, per marketplace reports and per return before filing.
6. Keep records for the longest period: 3.5 years after filing in Illinois, six years in Canada, 72 months after the annual return due date in India.

Worked example

Asha, in Aurora, sells handmade textiles online to customers in Illinois, Ontario and Pune. She is registered in Illinois and files ST-1 monthly: October sales by November 20, 2026 and November sales by December 21. Whether Canadian GST/HST applies to her Ontario sales depends on her situation, so she asks her Canadian CPA; her Indian Chartered Accountant handles the GST side of the Pune shipments. One product can create three filings on three calendars.

Mistakes to avoid

• Assuming a sales tax permit in one state or country covers any other.
• Using the wrong local rate for Illinois destination-based sales; the Tax Rate Finder gives the rate by delivery address.
• Ignoring the requirement to file nil returns in Canada and India.
• Missing a notified extension in India or relying on an outdated rate chart.

How we can help

We are a CPA firm in the Aurora area. We register and file Illinois sales tax returns and help with U.S. nexus questions. For Canadian GST/HST and Indian GST we coordinate with your Canadian CPA and Indian Chartered Accountant, who file under their own law, so your sales reports agree in all three places. See sales tax and GST compliance and sales tax for foreign sellers.

Frequently asked questions

General information only. It is not tax, legal, accounting or immigration advice for your situation, and rules change; confirm the current rules with the official source or a licensed professional in the relevant country.