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Illinois Employer Tax Information

To sign up for online payroll through Square in Illinois, you must be registered as an employer with the Illinois Department of Revenue (IDOR) and Department of Employment Security (IDES), and provide us with your Illinois Unemployment Account Number and Unemployment Insurance (UI) Contribution Rate.

Add Your Illinois Payroll Account Numbers to Square Payroll

You must be a registered employer to have an Illinois Unemployment Account Number and Illinois Taxpayer ID Number. Registration is required in order to acquire both of these numbers and we must have these numbers in order to make Illinois state tax payments and filings on your behalf.

Don’t Have Your Illinois Payroll Account Numbers?

To get your Illinois Payroll Account Numbers, register online with MyTax Illinois. After you complete registration, you will receive your Illinois Unemployment Account Number and Taxpayer ID Number.

Square Payroll only requires the first seven digits (XXXXXXX) of your Unemployment Account Number. Your Taxpayer ID Number (also known as an Illinois Department of Revenue [IDOR] Account ID Number or Illinois Business Tax number [IBT number]) will typically match your nine digit (XX-XXXXXXX) Federal Employment Identification Number (EIN) followed by a three-digit (XXX) Sequence Number.

Learn how to locate or obtain an EIN.

Can’t Locate Your Illinois Unemployment Account Number and/or Taxpayer ID Number?

To locate your Unemployment Account Number:

  • Log in to your Mytax Illinois Account.

  • Locate your Unemployment Account Number on any previously filed Employer’s Contribution & Wage Report (Form UI-3/40).

  • Locate your Unemployment Account Number on the Notice of Contribution Rate sent by IDES in December each year.

To locate your Taxpayer ID Number:

Add Your Unemployment Contribution Rate to Square Payroll

You must provide your UI Contribution Rate when signing up for Square Payroll so we can accurately compute this tax. To locate your UI Contribution Rate:

  • If you are a new employer, you will receive your Unemployment Contribution Rate after you complete registration on MyTax Illinois. The UI Contribution Rate includes the Fund Building Rate.

  • If you are an existing employer switching to Square Payroll, you can look your rate up online by logging in to your MyTax Illinois Account or locate it on the Notice of Contribution Rate that IDES mails each December. The UI Contribution Rate includes the Fund Building Rate.

  • If you can’t find your UI Contribution Rate, call IDES at 800-247-4984.

You are responsible for ensuring Square Payroll has the correct UI Contribution Rate for your business. If you need to update your rate, you can do so from the Tax Info tab in your online Square Dashboard.

Illinois State Tax Details

Square Payroll processes the following per the frequency below to the listed state agencies:

Agency Name Frequency
Department of Economic Security (IDES) Monthly Wage Report Monthly
Unemployment Insurance Payment Quarterly
Employer's Contribution and Wage Report (UI-3/40) Quarterly
New Hire Report Per New Employee
Department of Revenue (IDOR) Department of Revenue Payment Coupon (IL-501) Monthly
Withholding Income Tax Return (IL-941) Quarterly
Wage and Tax Statement (IL W-2) Annually

Review a full list of tax resources for all Square Payroll supported states.