Deadlines run on different clocks: fixed dates, a company's anniversary month, and dates that slide to the next business day over a weekend. The Nine-Pin Rolling Calendar below shows the next nine dated pins, and the table shows the dates that return every year. Dates marked derived follow from a rule, not from a posted 2027 calendar. Dates change, so confirm each one at the source.
- Form 941 and IL-941 due for the third quarter (October 31 is a Saturday); federal Nov 10 if all tax was deposited on time
- Monthly payroll tax deposits for October wages, federal and Illinois
- Social Security wage base rises to $192,300; Illinois non-compete earnings floor rises to $80,000
- Fourth Illinois individual estimated tax installment for tax year 2026
- Fourth-quarter IL-941 due; Forms W-2, W-3 and 1099-NEC derived to the same day (January 31 is a Sunday)
- Current two-year Cook County general business license period ends
- OSHA online injury data for 2026 due from covered employers (derived from the fixed March 2 rule date)
- Illinois rule on employment criteria with a discriminatory effect begins
- Employers with a final adverse discrimination ruling in 2026 report it to IDHR
Source: IRS Pub. 509 (2026), Illinois Pub. 131-D (2026), Federal Register, eCFR, Illinois statutes, IDHR, Cook County
Dates that recur each year
| Usual date (calendar-year filers) | What is due | Law and level | Year checked |
|---|---|---|---|
| 15th of each month | Monthly payroll tax deposits | FICA (federal); Income Tax Act (Illinois) | Nov 16, 2026 |
| Apr 30, Jul 31, Oct 31, Jan 31 | Quarterly Form 941 and IL-941 | FICA (federal); Income Tax Act (Illinois) | Apr 30, Jul 31, Nov 2, 2026 |
| January 31 | W-2, W-3, 1099-NEC, Forms 940 and 945 | FICA and IRC (federal) | Feb 2, 2026, for 2025 |
| Jan 15, Apr 15, Jun 15, Sep 15 | Individual estimated tax | Income Tax Act (Illinois) | Apr 15, Jun 15, Sep 15, 2026 |
| 20th of the month after the period; quarterly Apr, Jul, Oct, Jan 20; annual Jan 20 | Sales tax return, Form ST-1 | Retailers' Occupation Tax Act (Illinois) | Statute read Oct 2026 |
| Feb 1 to Apr 30 | Post the OSHA 300A injury summary | OSHA (federal) | Rule in force in 2026 |
| March 2 | OSHA online injury data | OSHA (federal) | Mar 2, 2026 |
| 15th day of month 3 after year end | Federal partnership and S corporation returns; Illinois IL-1120-ST | IRC (federal); Income Tax Act (Illinois) | Mar 16, 2026, federal |
| April 15 (15th day of month 4) | Federal C corporation returns; Illinois IL-1065, IL-1120, IL-1040 | IRC (federal); Income Tax Act (Illinois) | Apr 15, 2026 |
| April 15, then October 15 | FBAR, if foreign accounts topped $10,000 in total at any time | Bank Secrecy Act (federal) | Apr 15, Oct 15, 2026 |
| Within the 60 days before the anniversary month | LLC and corporation annual report, $75 | LLC Act; Business Corporation Act (Illinois) | 2026 |
| July 1 | Cook County minimum wage can change each year | Minimum Wage Ordinance (Cook County) | Jul 1, 2026: $15.40 |
| July 1 | Employers with a final adverse ruling in the prior year report it to IDHR | Human Rights Act (Illinois) | Jul 1, 2026 |
Guides: FICA, Illinois income tax, sales and use tax, OSHA, FBAR and Cook County minimum wage.
Frequently asked questions
Do federal and Illinois payroll deposits follow the same schedule?
Not necessarily. Each system tests payroll tax history separately. Federal monthly depositors reported $50,000 or less in the July 1 to June 30 lookback. Illinois assigns the semi-weekly schedule when lookback withholding was over $12,000, and a monthly payer moves to semi-weekly after a quarter above $12,000.
Does an extension move the payment date for Illinois income tax?
No. The Illinois Department of Revenue says tax due is still payable by the original due date, even with an extension of time to file.
How is the annual report date for an LLC or corporation set?
By the anniversary month, which depends on the month the entity was formed. The report is filed in the 60 days before that month begins. A late LLC faces a $100 penalty; a late corporation faces a penalty of 10% of its franchise tax due.
Official sources
- IRS: Publication 509, Tax Calendars (2026)
- Illinois Department of Revenue: Publication 131-D, withholding due dates (2026)
- OSHA: Injury Tracking Application
- Federal Register: Social Security cost-of-living increase and other determinations for 2027
- Illinois Department of Human Rights: Report adverse judgments and rulings
This page is a plain-language summary. The official source controls if there is any difference.