State guide
How to Register for Illinois Payroll Taxes
Hand your IDES and IDOR registrations to a dedicated tax manager who files them and follows up until your numbers arrive, or use the step-by-step guide below.
Last updated:
At a glance
2 agencies, 1 portal: MyTax Illinois
Register with IDES within 30 days
3.350% entry UI rate for 2026
4.95% flat withholding
Done for you
Rather not work through MyTax Illinois yourself?
Skip the paperwork. Your dedicated PayAdvisors tax manager registers you with the state and gets your tax IDs for you. In Illinois that covers IDES and IDOR, followed up until both accounts are confirmed.
- Your own tax manager, with a name and a direct line
- REG-1 and REG-UI-1 completed and filed with you, inside the 30-day window
- Follow-up with IDES and IDOR until your accounts are live
- Account numbers and payment schedule sent to you before first payroll
Real, hands-on help from a person, not a form wizard. Book it alone or pair it with managed payroll.
Quick answer
Illinois payroll tax registration at a glance
Illinois uses one online portal, MyTax Illinois, for two agencies. The Illinois Department of Employment Security (IDES) handles unemployment insurance (UI), and the Illinois Department of Revenue (IDOR) handles income tax withholding. Each gives you its own account.
IDES wants a new business registered within 30 days of start-up. The 2026 entry UI rate is 3.350% on the first $14,250 of each worker's wages, and Illinois withholding is a flat 4.95%.
Who must register
Who has to register in Illinois
Illinois ties UI registration to start-up and withholding to wages.
| Situation | What Illinois requires |
|---|---|
| New business with employees | Register with IDES within 30 days of start-up (820 ILCS 405/1800). The REG-UI-1 is the report IDES uses to determine liability |
| Household employer | IDES liability applies if you paid domestic workers $1,000 or more in cash wages in a calendar quarter, this year or any of the four preceding years |
| Anyone paying Illinois wages subject to withholding | Register with IDOR as a withholding agent and have each employee complete Form IL-W-4 |
Registration steps
How to register in MyTax Illinois
One portal, two registrations.
- Open MyTax Illinois and choose "Register a new business (Form REG-1)."
- Complete the IDOR withholding registration. Online confirmation generally comes in 1 to 2 days. A mailed paper REG-1 generally takes 6 to 8 weeks.
- Complete the IDES REG-UI-1 inside MyTax Illinois, within 30 days of start-up. A paper version exists. Household employers now also register with the REG-UI-1 and file the annual UI-HA.
- Watch for your payment schedule. IDOR puts new registrants on monthly payments with a quarterly return.
- Collect Form IL-W-4 from each employee so you know their Illinois allowances.
Questions
IDES Employer Hotline: 1-800-247-4984. IDOR business registration: 217 785-3707.
Not your job
Two agencies, one deadline clock
The 30-day IDES clock starts at start-up, while you are also hiring, setting pay and opening accounts.
On your own
- REG-1 and REG-UI-1 questions on your own
- Tracking two account numbers and a payment schedule
- Waiting on confirmations while payday approaches
With your PayAdvisors tax manager
- One tax manager files both with you
- We chase IDES and IDOR until accounts are live
- You get confirmed numbers, ready to run payroll
Your tax manager handles it for you.
Prepare
Details to gather first
These answers drive both forms.
- Your federal EIN (without one, IDOR assigns a temporary tax account number)
- Legal name, ownership and start-up date, for the 30-day IDES deadline
- Whether you bought all or part of an Illinois business, which IDES handles separately
- Household wages by quarter if you employ domestic workers
- How many employees you have, since 25 or more changes how you file UI reports
Accounts
What you end up with
Two accounts and a rate, each from a different agency.
- An IDES UI account number for the quarterly UI-3/40 and contributions.
- An IDOR withholding account on the monthly payment and quarterly return schedule.
- A UI contribution rate. New employers start at the entry rate for their NAICS sector.
2026 numbers
Illinois payroll tax rates for 2026
IDES publishes UI figures in the EA-50 each year. Withholding is a single rate.
| Item | 2026 figure |
|---|---|
| Standard entry UI rate | 3.350%, including the 0.550% fund building rate |
| Entry rate, NAICS sector 56 (administrative support and waste management) | 3.450% |
| UI rate range | 0.750% to 7.050% |
| UI wage base | First $14,250 per worker |
| Small employer cap | An experience-rated employer whose rate is above 5.400% and whose quarterly wages are under $50,000 pays 5.400% that quarter |
| Income tax withholding | 4.95% flat (subtract exemptions, then multiply) |
Pitfalls
Illinois mistakes that cost time
Watch these during your first year.
- Missing the 30-day window. IDES counts from start-up, not from the first quarterly report.
- Filing paper with 25 or more employees. Employers with 25 or more employees in the prior year must file the UI-3/40 electronically.
- Looking for an annual withholding reconciliation. Illinois has none. Each IL-941 carries the detail, and every IL-941 must be filed electronically.
- Assuming you stay monthly. If withholding in the July 1 to June 30 look-back period tops $12,000, IDOR moves you to semi-weekly payments.
- Mailing the REG-1 when you are in a hurry. Paper takes 6 to 8 weeks against 1 to 2 days online.
Related duties
Other Illinois employer obligations
Separate laws, same first payroll.
- Workers' compensation. With even one employee, including a part-time employee, you must carry coverage. See the Workers' Compensation Commission.
- New hire reporting. Report new employees within 20 days of their first day on payroll. IDES runs the Illinois registry.
- Minimum wage. $15.00 an hour for workers 18 and older. Tipped employees may be paid 60% of the minimum.
- Paid Leave for All Workers Act. Employees earn at least 1 hour of paid leave for every 40 hours worked, up to 40 hours in a 12-month period, or you can frontload the leave. This applies outside Chicago and Cook County, which have their own paid leave ordinances.
Filing calendar
Illinois deadlines after registration
Recurring filings for IDES and IDOR.
- UI-3/40 and contributions: due April 30, July 31, October 31 and January 31. Some employers also report wages monthly.
- IL-501 withholding payments: monthly payments are due the 15th of the following month. Semi-weekly payers follow the Wednesday and Friday schedule.
- IL-941 return: quarterly, due the last day of the month after the quarter, filed electronically.
- W-2s: give employees their copies before January 31.
- Household employers: file the annual UI-HA.
Official links
Illinois agency links
Official forms, rates and guidance.
Illinois registration questions
How do I register for Illinois payroll taxes?
Through MyTax Illinois. The REG-1 sets up IDOR withholding and the REG-UI-1 sets up your IDES unemployment insurance account.
How long do I have to register with IDES?
Within 30 days of start-up.
How long does Illinois withholding registration take?
Online, confirmation is generally available in 1 to 2 days. A paper REG-1 generally takes 6 to 8 weeks.
What is the Illinois new employer UI rate for 2026?
3.350% for most new employers, or 3.450% in NAICS sector 56, on the first $14,250 of wages.
What is the Illinois withholding rate?
4.95% for 2026, applied after subtracting the employee's exemptions.
Do I file an annual Illinois withholding reconciliation?
No. Illinois does not have one. You file the quarterly IL-941 electronically.
I am the sole employee of my S corporation. What do I need in Illinois?
If you take wages, you need IDOR withholding, and you should complete the IDES liability report. A dedicated tax manager can handle both as part of our S corp payroll package.
Does Illinois require workers' compensation for one employee?
Yes. Even one part-time employee requires coverage, with rare exceptions.
How is registration priced?
Most states issue two IDs, one for withholding and one for unemployment insurance. Pricing depends on the states and accounts involved. We'll quote it on a quick consultation.
Is this tax advice?
No. This guide summarizes official IDES, IDOR, Department of Labor and Workers' Compensation Commission material. For your own facts, ask your CPA or tax advisor.
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Next step
Let us open your Illinois accounts
A dedicated tax manager files with IDES and IDOR, stays on the agencies until each account is confirmed and gives you everything you need for your first payroll. Send us your start-up date and we will handle the rest.
About this guide
Last verified and sources
Last verified October 26, 2026 against the Illinois Department of Employment Security, Department of Revenue, Department of Labor and Workers' Compensation Commission. This guide is general information, not tax or legal advice.
Related
- State payroll tax registration (all states)
- California payroll tax registration guide
- Arizona payroll tax registration guide
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- Kentucky payroll tax registration guide
- Oklahoma payroll tax registration guide
- Connecticut payroll tax registration guide
- Iowa payroll tax registration guide
- Kansas payroll tax registration guide
- Arkansas payroll tax registration guide
- New Mexico payroll tax registration guide
- Payroll setup for new businesses
- Payroll tax filing and compliance
- S corp payroll
- S corp payroll setup checklist
Sources
- Illinois Department of Employment Security, Are You a New Employer?
- Illinois Department of Employment Security, Employer Tax Information
- IDES, EA-50 Employers' Contribution Rates for 2026 (PDF)
- IDES, Employer FAQs
- Illinois Department of Revenue, Publication 130, Who is Required to Withhold Illinois Income Tax (PDF)
- Illinois Department of Revenue, Publication 131, Withholding Income Tax Payment and Filing Requirements (PDF)
- Illinois Department of Revenue, 2026 IL-700-T Illinois Withholding Tax Tables
- Illinois Department of Revenue, Business Registration
- Illinois Department of Labor, Minimum Wage Law
- Illinois Department of Labor, Paid Leave for All Workers Act FAQ
- Illinois Workers' Compensation Commission, Insurance