Illinois Payroll Compliance Deadlines 2026 | Payroll Freedom

Last updated: September 23, 2026

Illinois payroll compliance deadlines aren’t hard. However, there are a lot of them, and they come from two different agencies that don’t talk to each other.

The Illinois Department of Revenue (IDOR) handles withholding. The Illinois Department of Employment Security (IDES) handles unemployment and new hire reporting. As a result, missing a date with either one means two separate penalty notices to sort out. Below are the seven Illinois payroll compliance deadlines every employer should have on the calendar. Each one is sourced to the agency that sets it.

What Are the Illinois Payroll Compliance Deadlines?

Here’s the short answer. Illinois payroll compliance deadlines fall into seven buckets:

1. New hire reports to IDES: within 20 days of each hire.
2. Withholding payments to IDOR: monthly by the 15th, or semi-weekly.
3. Form IL-941 quarterly withholding returns: April 30, July 31, October 31, and January 31.
4. Form UI-3/40 quarterly unemployment reports: same four dates.
5. Monthly wage reports to IDES: required for employers with 25 or more workers last year.
6. W-2s to IDOR: January 31, filed electronically.
7. Illinois Secure Choice: a registration deadline for newly covered employers, recently November 1.

If a due date lands on a weekend or state holiday, IDOR moves it to the next business day. The federal deadlines sit on top of all this. Our complete compliance guide covers the IRS side.

1. New Hire Reporting: 20 Days, Contractors Included

First, every Illinois employer must report new hires to IDES within 20 days. It’s the most familiar of the Illinois payroll compliance deadlines. Still, the change most owners missed came in 2024.

Under Public Act 103-0343, the definition of “newly hired employee” now includes independent contractors. Starting January 1, 2024, a new 1099 contractor gets reported just like a new W-2 employee. IDES’s new hire reporting page now asks for both.

Rehires also count. According to the Illinois New Hire Directory, anyone returning after at least 60 consecutive days off payroll must be reported again. That includes returns from layoffs, furloughs, and unpaid leave, because each one creates a gap.

Here’s what we see. Owners who use contractors for one-off jobs rarely think of them as “hires.” Illinois, however, does. If you’re unsure how a worker should be set up in the first place, our guide to classifying your first hire is a good starting point. For actual classification decisions, though, talk to an employment attorney.

2. Withholding Payments: Monthly or Semi-Weekly

Illinois doesn’t let you choose your payment schedule. Instead, IDOR assigns you one of two.

• Monthly: payments are due by the 15th of the following month. New employers start here automatically.
• Semi-weekly: payments are due Wednesday for amounts withheld the prior Wednesday through Friday. They’re due Friday for amounts withheld Saturday through Tuesday. Also, semi-weekly payers must pay electronically.

Here’s the trap. Per IDOR’s withholding income tax guidance, you move to semi-weekly if you withheld more than $12,000 during the look-back period. However, if you exceed $12,000 during a single quarter, it’s your responsibility to start paying semi-weekly the next quarter. IDOR doesn’t necessarily send a reminder first.

For a growing business, that switch can happen mid-year without anyone noticing. Then late-payment penalties start from each missed due date.

3. Form IL-941: Quarterly, Electronic, No Exceptions

Of all the Illinois payroll compliance deadlines, this one has the least wiggle room. Every Illinois employer files Form IL-941 each quarter. The due dates are the last day of the month after the quarter ends:

• Q1 (January–March): April 30
• Q2 (April–June): July 31
• Q3 (July–September): October 31
• Q4 (October–December): January 31

According to IDOR Publication 131, all IL-941 returns must be filed electronically. If you can’t, you have to request a waiver on Form IL-900-EW. In addition, you file even in a quarter with no withholding.

One thing that surprises owners who also run payroll in Wisconsin: unlike the federal system and Wisconsin’s WT-7, Illinois has no annual withholding reconciliation return. Instead, the four quarterly IL-941s are the reconciliation. That’s why each one has to be right.

4. Form UI-3/40: Quarterly Unemployment Reports

Your unemployment filings go to IDES, not IDOR, on the same four quarterly dates. Also, the UI-3/40 is due even if you owe nothing that quarter.

For 2026, Illinois unemployment tax applies to the first $14,250 of each employee’s wages. According to the IDES 2026 rate notice, most new employers pay 3.35%, while experienced employers range from 0.75% to 7.05%, including a 0.55% fund-building rate. Because the tax stops at $14,250 per person, most of it lands in the first quarter or two of the year. So plan cash flow accordingly.

5. Monthly Wage Reports: The Illinois Payroll Deadline Most Employers Miss

This is the one that catches people. IDES requires monthly wage reports from employers with a cumulative total of 25 or more employees in the prior calendar year.

The key word is cumulative. It counts every worker you paid during the year, not your headcount on any given day. As a result, a 15-person restaurant with high turnover can easily cross 25. For example, if 12 people leave and are replaced during the year, that’s 27 workers reported.

Once you’re in, you then file eight extra reports a year. They cover the first and second month of each quarter, and each one is due the last day of the following month. However, you still file the quarterly UI-3/40 as well.

6. W-2s to IDOR: The January 31 Illinois Payroll Deadline

It’s the last of the Illinois payroll compliance deadlines to hit each January. Illinois wants copies of your W-2s by January 31. IDOR’s W-2 filing page is blunt about it: electronic filing is mandatory, and IDOR does not accept paper W-2s by mail.

For example, you can enter them in MyTax Illinois, upload a CSV file, or use the formatted electronic transmission program. The federal W-2 deadline for 2026 forms is February 1, 2027, since January 31 falls on a Sunday. So treat Illinois’s date as the one that counts. Our year-end payroll checklist walks through the rest of January.

7. Illinois Secure Choice: The Deadline on Your Notice

It isn’t a tax filing, but it belongs on your list of Illinois payroll compliance deadlines because it carries real penalties. Illinois Secure Choice requires certain employers to either offer a qualified retirement plan or register employees in the state program.

According to the Illinois Secure Choice registration rules, the law applies to employers that had 5 or more employees in the previous year, have been in business at least two years, and don’t sponsor a qualified retirement plan. Each year, the program notifies newly covered employers, and in recent years their deadline to register or certify an exemption has been November 1. Under the Illinois Administrative Code, penalties are $250 per employee for the first year of noncompliance and $500 per employee for each year after.

So if you received a Secure Choice notice this year, check the deadline printed on it now. If you’d rather offer your own plan instead, our retirement plan options can take the place of Secure Choice.

Your Illinois Payroll Compliance Deadlines Calendar

Here’s how it all lines up across a year. Meanwhile, monthly and semi-weekly payment dates repeat throughout.

Date	What’s due	Agency
15th of every month	Withholding payment (monthly payers)	IDOR
Last day of the month after Jan, Feb, Apr, May, Jul, Aug, Oct, Nov	Monthly wage report (25+ workers)	IDES
January 31	Q4 IL-941, Q4 UI-3/40, W-2s to IDOR	IDOR / IDES
April 30	Q1 IL-941, Q1 UI-3/40	IDOR / IDES
July 31	Q2 IL-941, Q2 UI-3/40	IDOR / IDES
October 31	Q3 IL-941, Q3 UI-3/40	IDOR / IDES
Date on your notice (recently November 1)	Secure Choice registration or exemption (newly covered employers)	State Treasurer
Within 20 days of each hire	New hire report, including contractors	IDES

What This Means for Your Illinois Payroll Compliance

What this means for you: the Illinois payroll compliance deadlines themselves aren’t the problem. Instead, the triggers are. The $12,000 semi-weekly switch, the 25-worker monthly reporting rule, and the contractor reporting change all kick in quietly. And nobody sends a warning first.

So once a year, check three numbers: your quarterly Illinois withholding, your total workers paid last year, and your count of new contractors. If any of them moved, then your deadlines may have too.

Running payroll on both sides of the state line? See the Wisconsin version of this list. Also, if you’re still figuring out how much help you need, our guide to choosing the right payroll package takes about five minutes.

Illinois Payroll Deadlines FAQ

When is Form IL-941 due?

Form IL-941 is due quarterly by the last day of the month after each quarter ends: April 30, July 31, October 31, and January 31. It must be filed electronically, even if you withheld nothing.

Do I have to report independent contractors to IDES?

Yes. Since January 1, 2024, Illinois requires employers to report newly hired independent contractors to IDES within 20 days, the same as new employees.

How do I know if I’m a monthly or semi-weekly payer in Illinois?

IDOR assigns your schedule based on your withholding during the look-back period. New employers start on monthly. If you exceed $12,000 in withholding in a quarter, you must switch to semi-weekly the next quarter on your own.

Can I mail my W-2s to the Illinois Department of Revenue?

No. IDOR requires W-2s to be filed electronically by January 31 and does not accept paper copies by mail.

This article is provided for general informational purposes only and does not constitute tax, legal, or payroll advice. Illinois filing requirements, thresholds, and rates change, and your assigned schedules depend on your specific account. Before acting on anything you read here, please consult a qualified advisor, including, we hope, us. Reach out to Payroll Freedom for guidance specific to your business.

About the Author

Frank Fiore, CPA — President & Visionary, Payroll Freedom

Frank Fiore has spent 20+ years helping small business owners navigate Illinois payroll filings, deposit schedules, and the deadlines that come with them. Payroll Freedom serves clients from offices in Mundelein, IL and Grafton, WI.