Important 2026 IRS deadlines for your business

January 15th – 4th quarter 2025 estimated tax payment deadline (Form 1040-ES).

January 31st (falls on Saturday → due Monday, February 2, 2026) –
• Employers must send W-2 forms to employees
• 1099-NEC / 1099-MISC due to contractors
• Copy B of Form 3921 due to employees (ISO exercises)
• Form 940 (Federal Unemployment Tax Return) due

February 2nd –
• File W-2 and 1099 forms with the Social Security Administration
• Provide Affordable Care Act (ACA) forms to employees

February 28th (falls on Saturday → due Monday, March 2, 2026) –
• Paper filing deadline for Forms 1099-NEC, 1099-MISC, and W-2
• Paper filing deadline for Form 3921

March 16th (March 15 is Sunday) –
• Tax returns due for S Corporations (Form 1120-S)
• Tax returns due for Partnerships (Form 1065)
• Schedule K-1 must be furnished to partners/shareholders
• Deadline to elect S Corporation status for 2026 (Form 2553)

March 31st –
• Electronic filing deadline for Form 3921

April 15th –
• Tax Day
• Individual tax returns due (Form 1040)
• C Corporation tax returns due (Form 1120)
• 1st quarter 2026 estimated tax payment deadline
• Deadline to file Form 4868 (individual extension)
• Deadline to file Form 7004 (business extension)

June 15th –
• 2nd quarter 2026 estimated tax payment deadline

September 15th –
• 3rd quarter 2026 estimated tax payment deadline
• Extended filing deadline for S Corporation and Partnership returns

October 15th –
• Extended filing deadline for Individual and C Corporation returns

December 15th –
• 4th quarter estimated tax payment deadline for corporations
(Fiscal year ending December 31)