January 2026
January 15
- Fourth quarter estimated tax payment for 2025 due (Form 1040-ES)
January 31 (Saturday → Due Monday, February 2, 2026)
- W-2 forms due to employees
- 1099 forms due to contractors
- Copy B of Form 3921 due to employees (for ISO exercises)
- Form 940 (Federal Unemployment Tax Return) due
February 2026
February 2
- File W-2 and 1099 forms with the Social Security Administration
- Provide Affordable Care Act (ACA) forms to employees
February 28 (Saturday → Due Monday, March 2, 2026)
- Paper filing deadline for Forms 1099-MISC, 1099-NEC, and W-2
- Paper filing deadline for Form 3921
March 2026
March 16 (March 15 is Sunday)
- Tax returns for S corporations (Form 1120-S) and partnerships (Form 1065) due
- Furnish Schedule K-1 to partners/shareholders
- Deadline to elect S corporation status for 2026 (Form 2553)
March 31
- Electronic filing deadline for Form 3921
April 2026
April 15
- Tax returns for C corporations (Form 1120) and individuals (Form 1040) due
- First quarter estimated tax payment for 2026 due
- Deadline to file for an automatic extension (Forms 4868 or 7004)
June 2026
June 15
- Second quarter estimated tax payment for 2026 due
September 2026
September 15
- Third quarter estimated tax payment for 2026 due
- Extended deadline for S corporation and partnership returns
October 2026
October 15
- Extended deadline for C corporation and individual returns
December 2026
December 15
- Fourth quarter estimated tax payment for corporations (fiscal year ending December 31)