Illinois Payroll Tax and Registration Guide

Use this checklist to make sure you’ve covered everything required to set up your account as a Illinois employer so OnPay can accurately file and pay taxes on your behalf: 

OnPay handles the filing of all state and local taxes for businesses in Illinois, including:

If you are an existing employer who has previously run payroll in Illinois, you likely already have the IDs and online accounts needed for OnPay to process your tax filings.

If you are a new employer in Illinois, you will need to register your business with the Illinois Department of Revenue and the Illinois Department of Employment Security. This must be completed for OnPay to be able to file and pay your Illinois taxes.

Withholding Tax Account Number

Existing Illinois Employer: 

This account number will include your Federal EIN, and you can find the ID on your Illinois Withholding Income Tax Return (IL-941).

New Illinois Employer: Register with the Illinois Department of Revenue 

• Electronically register through MyTax Illinois (approximately one to two days to process)
• Complete and mail Form REG-1, Illinois Business Registration Application, to the address on the form (Form REG-1 is available on their web site as a fill-in and savable form. 
• Registration forms are also available by calling the Department of Revenue at 1-800 356-6302.
• You'll be able to register using your Federal EIN. Your account number will include your Federal EIN.

Existing Illinois Employer: 

• Your Unemployment account number and your Illinois UI Contribution Rate will be on the Notice of Contribution Rate that you receive from the Illinois Department of Employment Security (IDES) each year.
• Your Unemployment Tax Rate can be found in the far contribution rate box of the Tax Rate Notice. New employers generally have a rate of 3.525% for SUTA with a wage base of $12,960.

New Illinois Employer: Register with the Department of Employment Security

• Register your business with IL Department Employment Security.
• You'll instantly be issued an Unemployment Account Number in the format of Example: 1234567-8 or 1234567. It is important to note that your unemployment tax number is NOT the same as your FEIN. The last digit of your Unemployment number is called the check digit and the department will often omit it from correspondence. If you don't receive your Unemployment ID, please call the agency at (800)247-4984 to request it.

OnPay works with government entities on your behalf, reporting new hires to state labor departments, calculating tax rates, and filing financial reports. To do this effectively, you will need to add OnPay as your third party agent by following the instructions below.

TPA for the Department of Revenue:

1. Log In to your MyTax Illinois Account. If you do not have an account with MyTax Illinois, you will have to register.
2. Select "Manage My Profile"
3. Select "More..."
4. Select "Manage Third Party Access"
5. Set Third Party Access as follows:
   1. Allowed : Yes
   2. Default Access : Third Party
   3. Default Account Access : File 

TPA for the Department of Labor:

1. Log In to your MyTax Illinois Account. If you do not have an account with MyTax Illinois, you will have to register.
2. Click the 'View all account options' hyperlink under Unemployment Insurance
3. Under Power of Attorney (POA) > Click 'Add Agent'
4. Select 'Search by agents name' and then type in 'OnPay' next to Enter Agents Name
5. Click 'Next'
6. Check 'Select'
7. Click 'Next'
8. Keep 'Full access to view and manage' selected and check the following options:
   1. UI Employer Contribution Report
   2. Rate Notice
9. Click Next
10. Click box next to 'Agree'
11. Click Submit

Power of attorney

You will also need to complete an Illinois Power of Attorney form. Follow the instructions in this article to do so.

Email us the completed Power of Attorney forms to hello@onpay.com