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Calendar and tax documents highlighting federal and Illinois tax deadlines reviewed by Hym

Federal & Illinois Tax Deadlines for Individuals and Businesses

Stay compliant with accurate federal and Illinois tax due dates, curated and monitored by a CPA-led firm serving Chicago individuals and small businesses.

CPA Guidance • Secure Uploads 

Federal Tax Deadlines

IRS Form
Deadline
Form 1040
April 15
Form 4868
April 15
Form 1065
March 15
Form 1120-S
March 15
Form 1120
April 15
Forms W-2 and 1099
January 31
Form 941
Quarterly
Form 940
January 31
Form 944
January 31

Need help meeting federal deadlines? Talk to a CPA

Illinois Tax Deadlines

Illinois Form
Deadline
IL-1040
April 15
IL-505-I
April 15
IL-1065
March 15
IL-1120-ST
March 15
IL-1120
April 15
W-2 and 1099
January 31
IL-941
Quarterly
IL-W-3
January 31

Illinois generally follows federal deadlines, but penalties and interest rules differ. CPA guidance is recommended for business owners and multi-state filers.

Get Illinois CPA Guidance

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