What Is Illinois Payroll Tax?
Illinois payroll tax refers to the state payroll taxes that employers must withhold from employee wages or pay directly to state agencies. These taxes fund unemployment benefits and the state's income tax system.
Illinois keeps its payroll tax structure relatively simple compared to states like California, New York, or Pennsylvania: there's no state disability insurance program, no local income tax layer, and no employment training tax. Illinois payroll taxes are administered by two separate state agencies the Illinois Department of Employment Security (IDES) for unemployment insurance, and the Illinois Department of Revenue for income tax withholding and employers need to register with both.
Most Illinois employers are responsible for two primary state payroll tax requirements:
Unemployment Insurance (UI), administered by IDES
Illinois Personal Income Tax withholding, administered by the Department of Revenue, at a flat rate
Because Illinois has no state disability insurance program and no local income tax (unlike neighboring states such as Pennsylvania or Ohio), employers generally have fewer moving parts to manage than in many other states but registering correctly with both state agencies from day one matters, since they don't share information with each other.
Illinois Payroll Taxes at a Glance
| Payroll Tax | Paid By | Purpose |
|---|---|---|
| Unemployment Insurance (UI) | Employer | Provides temporary income for eligible unemployed workers |
| Personal Income Tax (state) | Employee (withheld by employer) | Flat-rate state income tax withheld from employee wages |
Understanding this shorter list helps employers avoid over-complicating payroll setup Illinois payroll compliance centers on these two taxes, filed with two different agencies.
Illinois Employer Payroll Tax Responsibilities
Every employer with workers in Illinois has payroll tax responsibilities beyond simply issuing paychecks. Depending on your business, you'll generally need to:
Register your business separately with IDES (for unemployment insurance) and the Illinois Department of Revenue (for income tax withholding), typically through the state's MyTax Illinois portal.
Determine whether your business has met the wage or employment threshold that makes you liable for UI.
Calculate taxable wages up to the annual UI wage base.
Withhold state income tax at the flat rate from every paycheck.
Pay employer UI contributions.
File quarterly UI wage reports and income tax withholding returns.
Submit payments before their due dates.
Maintain payroll records for state compliance.
Many businesses automate these tasks using payroll software, reducing the risk of manual errors and missed deadlines particularly useful in Illinois given the two-agency registration requirement.
Understanding Illinois Unemployment Insurance (UI)
Unemployment Insurance is an employer-funded payroll tax that provides temporary financial assistance to eligible workers who lose their jobs through no fault of their own. In Illinois, it's administered by the Illinois Department of Employment Security (IDES).
Employers pay this tax directly it is never deducted from employee paychecks.
Illinois uses a two-layer rate system that makes it somewhat more complex and, historically, more expensive than many other states. Each employer's individual rate is based on a benefit ratio (unemployment benefits charged to the employer's account relative to taxable payroll), and that rate is then adjusted annually by a statewide "State Experience Factor," which rises or falls depending on the overall health of the Illinois unemployment trust fund. This means your rate can change from year to year even if your own claims history hasn't, simply because the statewide factor shifted.
Key Facts
Paid entirely by employers
Calculated on taxable wages up to Illinois's annual UI wage base, which IDES adjusts periodically
New employers pay a standard entry rate, which includes a Fund Building Rate layered on top of the base rate
Experience-rated employers (generally those with three or more years of payroll history) receive a rate based on their benefit ratio, further adjusted by the annual State Experience Factor
Must be reported to IDES every quarter
When You Become Liable for Illinois UI Tax
Not every business is liable for UI tax from day one. Illinois uses several different liability thresholds depending on the type of employer:
Most for-profit employers: liable once you pay $1,500 or more in wages during any single calendar quarter, or employ at least one worker for any part of a day in each of 20 different weeks in a calendar year
Nonprofit organizations: liable once you employ four or more workers during each of 20 different weeks in a calendar year
Domestic (household) employers: liable once you pay $1,000 or more in cash wages in a single calendar quarter
Agricultural employers: liable once you pay $20,000 or more in cash wages in a single quarter, or employ 10 or more workers for 20 different weeks
It's worth checking which threshold applies to your specific type of organization before assuming standard liability rules apply.
Illinois Personal Income Tax (PIT) Withholding
Illinois imposes a flat-rate personal income tax on wages there are no tax brackets to calculate, which makes Illinois's state withholding one of the more straightforward calculations among larger states.
Employers are responsible for:
Withholding the flat state rate from every paycheck, after applying the employee's exemption allowances
Reporting withholding to the Illinois Department of Revenue
Depositing withheld taxes according to a schedule based on total withholding liability
Filing quarterly withholding returns and year-end reconciliation, including W-2 filing with the state
Unlike Pennsylvania or Ohio, Illinois has no local income tax layer for employers to manage a flat state rate is the whole withholding calculation, regardless of which Illinois municipality an employee lives or works in.
Which Payroll Taxes Are Paid by Employers vs Employees?
| Tax | Employer Pays | Employee Pays |
|---|---|---|
| Unemployment Insurance (UI) | YES | NO |
| Personal Income Tax (state) | NO | Withheld from wages (flat rate) |
Illinois keeps this split simple: employers fund UI entirely out of pocket, while employees fund the entire state income tax withholding there's no shared-contribution tax like Pennsylvania's employee UC withholding, and no employer-funded disability or family leave tax like California or New York.
Illinois Payroll Tax Rates for Employers
Understanding current Illinois payroll tax rates is essential for calculating payroll accurately. Illinois's UI rates in particular can shift meaningfully year to year due to the State Experience Factor, so always verify your current rate with IDES before processing payroll.
Illinois Payroll Tax Rates at a Glance
| Payroll Tax | Who Pays | General Rate | Taxable Wage Base |
|---|---|---|---|
| Unemployment Insurance (UI) | Employer | Experience-based, adjusted annually by the statewide State Experience Factor; separate flat rate for new employers | Annual wage base set by IDES, adjusted periodically and generally higher than the federal minimum |
| Personal Income Tax (state) | Employee | Flat rate | Applies to wages after exemption allowances, no brackets |
According to IDES's most recent official rate notice (Form EA-50), the 2026 taxable wage base is $14,250, and the statewide State Experience Factor for 2026 is 102%. Note that third-party sources sometimes cite slightly different wage base and new-employer rate figures for Illinois always confirm your specific numbers directly from IDES's annual EA-50 report and your own rate notice rather than relying on secondary sources.
Instead of memorizing a specific rate, employers should focus on reviewing their annual IDES rate notice, tracking the current wage base, and filing returns on time.
Understanding Taxable Wages
Illinois UI tax applies to taxable wages up to the annual wage base set by IDES. Taxable wages generally include:
Hourly wages
Salaries
Bonuses
Overtime pay
Commissions
Certain taxable fringe benefits
Once an employee's wages for the year cross the annual UI wage base, no further UI tax is owed on that employee's wages for the remainder of the year. Illinois income tax withholding, by contrast, applies to wages after exemption allowances with no separate wage base cap.
Illinois Payroll Tax Filing Deadlines
Meeting payroll tax deadlines is just as important as calculating taxes correctly. Late filings or payments can lead to penalties and interest charges.
Unemployment Insurance (Form UI-3/40)
Illinois employers file unemployment insurance wage reports on a quarterly basis.
| Reporting Quarter | Filing Deadline |
|---|---|
| January – March | April 30 |
| April – June | July 31 |
| July – September | October 31 |
| October – December | January 31 |
State Income Tax Withholding
Illinois income tax withholding deposit frequency depends on the amount withheld, ranging from quarterly to more frequent schedules for larger withholders. Quarterly withholding returns (Form IL-941) are required regardless of deposit frequency, along with an annual reconciliation.
If a deadline falls on a weekend or state holiday, the due date generally moves to the next business day. Since Illinois requires filings with two separate agencies, it's worth tracking IDES and Department of Revenue deadlines independently rather than assuming a single combined filing covers both.
How to Register for Illinois Payroll Taxes
Before paying employees, businesses typically need to register separately with both IDES and the Illinois Department of Revenue, most commonly through the state's MyTax Illinois portal.
Registration establishes your unemployment insurance account with IDES and your withholding tax account with the Department of Revenue, allowing you to file wage reports, income tax withholding returns, and submit required payments.
Most employers should register once they meet the applicable liability threshold discussed above.
During registration, you'll generally need information such as:
Legal business name
Federal Employer Identification Number (EIN)
Business entity type
Business address
Owner or responsible party information
Date employees first performed services in Illinois
Estimated payroll information
Once registered, you'll receive an IDES account number for UI filings and a separate Illinois Business Tax (IBT) number for withholding tax filings.
How to File Illinois Payroll Taxes
Filing payroll taxes in Illinois involves two parallel but separate processes one for unemployment insurance, one for income tax withholding. A typical filing process includes:
Step 1: Calculate Employee Wages Determine each employee's gross wages, including regular pay, overtime, bonuses, commissions, and other taxable compensation.
Step 2: Calculate Payroll Taxes Determine your employer UI contribution based on your current IDES rate notice, and calculate employee income tax withholding at the flat state rate.
Step 3: Withhold Employee Income Tax Deduct Illinois state income tax from employee paychecks before issuing payment.
Step 4: Pay Employer UI Contributions Remit UI payments to IDES according to your assigned deposit schedule.
Step 5: File Payroll Tax Returns Submit Form UI-3/40 quarterly to IDES for unemployment insurance, and Form IL-941 quarterly to the Department of Revenue for income tax withholding.
Step 6: Maintain Payroll Records Keep detailed payroll records, wage reports, and payment confirmations in case of future audits or compliance reviews from either agency.
Following a consistent payroll process helps reduce mistakes and makes year-end reporting significantly easier.
Frequently Asked Questions
Who is required to pay Illinois payroll taxes?
Most businesses that hire employees in Illinois become liable for unemployment insurance once they meet certain wage or employment thresholds commonly $1,500 or more in wages during a calendar quarter, though thresholds differ for nonprofits, domestic employers, and agricultural employers. Liable employers must register with IDES and the Illinois Department of Revenue and comply with applicable payroll tax requirements.
What payroll taxes are employers responsible for in Illinois?
Illinois employers are generally responsible for two state payroll taxes: Unemployment Insurance (UI), paid entirely by the employer, and state Personal Income Tax withholding, deducted from employee wages at a flat rate. Illinois has no state disability insurance program and no local income tax layer.
How often do employers file Illinois payroll tax returns?
Unemployment insurance wage reports (Form UI-3/40) are filed quarterly with IDES. Income tax withholding returns (Form IL-941) are also filed quarterly with the Department of Revenue, though deposit frequency for withheld amounts can be more frequent depending on the amount withheld.
How do I register for Illinois payroll taxes?
Employers typically register separately with IDES (for unemployment insurance) and the Illinois Department of Revenue (for withholding tax), most easily done through the MyTax Illinois portal, once the applicable wage or liability threshold is met.
What happens if payroll taxes are filed late?
Late filings or payments with either agency may result in penalties, interest charges, or other compliance issues. Filing accurately and on time with both IDES and the Department of Revenue helps reduce the risk of unnecessary costs.
Does Illinois payroll tax apply to remote employees?
If an employee performs work that is subject to Illinois payroll tax rules, employers may have Illinois payroll tax obligations even if the company is based elsewhere. Since many employees work remotely across state lines, it's worth reviewing where services are actually performed to determine which state's rules apply.
Are Illinois payroll tax rates the same every year?
Not always. Illinois's UI wage base and the statewide State Experience Factor can both change from year to year based on the health of the state's unemployment trust fund, which in turn affects every employer's UI rate even those with an unchanged claims history. The flat income tax withholding rate has been comparatively stable but can also change through legislative action. Employers should review IDES's annual rate notice each year before processing payroll.
Can payroll software calculate Illinois payroll taxes automatically?
Many payroll platforms automatically calculate Illinois UI contributions and flat-rate income tax withholding, generate the required quarterly reports for both IDES and the Department of Revenue, and help employers meet filing deadlines. While automation can significantly reduce manual work, employers are still responsible for ensuring payroll information is accurate and up to date.
DISCLAIMER
This article is for general informational purposes only and doesn't constitute legal, tax, or accounting advice. Payroll tax rates and rules change frequently consult a qualified CPA or tax professional for guidance specific to your business.
