Illinois Sales Tax Registration

In Illinois it is called the Certificate of Registration. The Illinois Department of Revenue issues it.

Who has to register in Illinois, how to apply, what it costs, how long it takes, and what you file once you have it.

Illinois sales tax registration at a glance

What it is called: Certificate of Registration; Full name: Certificate of Registration (sales and use tax, Retailers' Occupation Tax). Number issued: Illinois Account ID (Sales and Use Tax Account ID) (8 digits, XXXX-XXXX).
Who issues it: Illinois Department of Revenue; Apply online through MyTax Illinois (Register a New Business, Form REG-1). Paper form: Form REG-1.
State fee: No state fee; No registration fee appears on IDOR's registration pages or in 35 ILCS 120/2a. IDOR may require a surety bond or irrevocable bank letter of credit of up to three times average monthly tax liability or $50,000, whichever is lower.
Processing time: About 1 to 2 business days; IDOR says a MyTax Illinois registration takes approximately one to two business days and a paper REG-1 four to six weeks. The Certificate is issued electronically and printed from MyTax Illinois.
Remote seller threshold: $100,000 in sales; Measurement period: 12-month lookback period. In effect since January 1, 2026.
Filing frequency: Monthly, quarterly or annual; IDOR assigns monthly or quarterly filing at registration. Quarterly if average monthly liability is $200 or less, annual if $50 or less; monthly otherwise. Retailers averaging $20,000 or more a month over the prior four quarters make quarter-monthly accelerated payments after IDOR notice.
State rate: 6.25%; Home-rule and non-home-rule city, county and district taxes add to the 6.25% state rate and are administered by IDOR. The state 1% tax on groceries ended January 1, 2026; cities and counties may impose a local 1% grocery tax by ordinance.

How to register in Illinois

Where to apply: Apply online with the Illinois Department of Revenue. MyTax Illinois (Register a New Business, Form REG-1)
Application form: Form REG-1, Illinois Business Registration Application. Form REG-1 (PDF)
What you need: An FEIN where the organization type requires one; corporations, LLCs and limited partnerships register with the Illinois Secretary of State first.
What the application covers: Retailers' Occupation Tax and Use Tax, local taxes administered by IDOR and withholding and other IDOR taxes on the same REG-1 (with schedules for liquor, tobacco, tire fee and others).
How long it takes: IDOR says a MyTax Illinois registration takes approximately one to two business days and a paper REG-1 four to six weeks. The Certificate is issued electronically and printed from MyTax Illinois.
What it costs: No registration fee appears on IDOR's registration pages or in 35 ILCS 120/2a. IDOR may require a surety bond or irrevocable bank letter of credit of up to three times average monthly tax liability or $50,000, whichever is lower.
Renewal: For retailers who file sales tax returns, the Certificate expires after one year and renews automatically unless IDOR says otherwise. Resellers who do not file returns must reapply every three years using a renewal packet IDOR sends.

After you register

How often you file: Monthly, quarterly or annual (Form ST-1). IDOR assigns monthly or quarterly filing at registration. Quarterly if average monthly liability is $200 or less, annual if $50 or less; monthly otherwise. Retailers averaging $20,000 or more a month over the prior four quarters make quarter-monthly accelerated payments after IDOR notice.
Due date: 20th of the month after the period.
Prepayments: Quarter-monthly payments due the 7th, 15th, 22nd and last day of the month for retailers with average monthly liability of $20,000 or more (22.5% of actual liability for the month, or 25% of the same month last year).
Rates and sourcing: The state rate is 6.25%. Home-rule and non-home-rule city, county and district taxes add to the 6.25% state rate and are administered by IDOR. The state 1% tax on groceries ended January 1, 2026; cities and counties may impose a local 1% grocery tax by ordinance. Sourcing: Sellers with an Illinois place of business generally source by where the selling activity occurs; since January 1, 2025 remote retailers and sales from out-of-state inventory use destination-based local rates.
Late returns: Late-filing penalty of 2% of the tax required to be shown on the return, up to $250, plus late-payment penalties and interest.

Illinois rules in plain English

In Illinois, you need a Certificate of Registration from the Illinois Department of Revenue (IDOR). You apply online in MyTax Illinois using Form REG-1, the Illinois Business Registration Application, or on the paper REG-1. IDOR says online registrations take about one to two business days and paper ones four to six weeks. IDOR's pages list no registration fee, but it can ask some applicants for a bond. Register with the Illinois Secretary of State first if you are a corporation or LLC, and get an FEIN if your business type needs one. Your certificate shows your Account ID in the format XXXX-XXXX and renews automatically each year while you file returns. You file Form ST-1 monthly or quarterly, as IDOR assigns, by the 20th of the next month. Small accounts can file yearly. The state rate is 6.25%, and IDOR also collects city, county and district taxes. Since January 2026, groceries carry no state tax, but many towns add 1%. The one mistake to avoid: using the wrong local rate. Rates depend on where you sell from, and remote sellers must use the buyer's address.

Sources: Illinois Department of Revenue · MyTax Illinois (Register a New Business, Form REG-1) · Form REG-1 (PDF)

More Illinois facts

From January 1, 2026, Illinois dropped the 200-transaction test; the only remote seller threshold is $100,000 in gross receipts over the 12-month lookback period (P.A. 104-0006). Source
The state 1% tax on qualifying food (groceries) ended January 1, 2026; municipalities and counties that filed ordinances may now impose a local 1% grocery tax, collected by IDOR. Source
Since January 1, 2025, remote retailers and retailers shipping from out-of-state inventory collect destination-based local Retailers' Occupation Tax, and must keep the customer's full ship-to address. Source
The Illinois Account ID on the Certificate of Registration has the format XXXX-XXXX, and the certificate must be displayed at the place of business. Source
Buyers use Form CRT-61, Certificate of Resale, and give their Illinois account ID or resale number. Source

We register you in Illinois

Answer a few questions about your business. We prepare your Illinois Certificate of Registration application, file it with IDOR, and send you the number. $199 per state. Any state fee is separate.

Start my Illinois registration

Illinois sales tax registration FAQ

Do I need to register for Illinois sales tax?

Anyone in the business of selling tangible personal property at retail in Illinois, including from an Illinois place of business, must hold a Certificate of Registration (35 ILCS 120/2a). Sellers with no physical presence must register after $100,000 in sales in Illinois (measurement period: 12-month lookback period).

How long does it take to get an Illinois Certificate of Registration?

IDOR says a MyTax Illinois registration takes approximately one to two business days and a paper REG-1 four to six weeks. The Certificate is issued electronically and printed from MyTax Illinois. Source: PIO-117 (R-01/26).

What does an Illinois Certificate of Registration cost?

No registration fee appears on IDOR's registration pages or in 35 ILCS 120/2a. IDOR may require a surety bond or irrevocable bank letter of credit of up to three times average monthly tax liability or $50,000, whichever is lower. Source: 35 ILCS 120/2a. Our fee to prepare and file the application is $199.

When do I file Illinois sales tax returns?

Filing frequency: monthly, quarterly or annual (Form ST-1). IDOR assigns monthly or quarterly filing at registration. Quarterly if average monthly liability is $200 or less, annual if $50 or less; monthly otherwise. Retailers averaging $20,000 or more a month over the prior four quarters make quarter-monthly accelerated payments after IDOR notice. Due date: 20th of the month after the period. Source: PIO-102 (effective Jan. 6, 2025), 86 Ill. Adm. Code 130.501, 130.535; 35 ILCS 120/3.

Do I need to register in Illinois as a remote seller?

Sellers with no physical presence must register after $100,000 in sales in Illinois (measurement period: 12-month lookback period). A marketplace facilitator meeting the same $100,000 lookback test is treated as the retailer for sales it facilitates and collects state and destination-based local Retailers' Occupation Tax (IDOR Bulletin FY 2026-12, https://tax.illinois.gov/research/publications/bulletins/fy-2026-12.html). Source: P.A. 104-0006; IDOR Bulletin FY 2026-12.

What happens if I sell in Illinois without an Illinois Certificate of Registration?

Selling at retail in Illinois without a Certificate of Registration is unlawful, and each day is a separate offense. Source: 35 ILCS 120/2a.

Nearby states

This page summarizes Illinois sales tax registration rules for general information and is not tax advice. Confirm current requirements with the Illinois Department of Revenue or your tax adviser. State rules last checked October 2, 2026.