Important Tax Deadlines 2026

Extended filing deadline (file extension using Form 4868): October 15, 2026.

The FBAR (FinCEN Form 114) filing deadline coincides with the federal income tax return due date. An automatic 6-month extension is allowed, generally until October 15.
Partnerships (Form 1065): March 16, 2026 (extended deadline: September 15, 2026), or the 15th day of the third month after the end of the partnership’s tax year for fiscal-year partnerships.
S Corporations (Form 1120-S): March 16, 2026 (extended deadline: September 15, 2026), or the 15th day of the third month after the end of the fiscal year.
C Corporations (Form 1120): April 15, 2026 (extended deadline: October 15, 2026), or the 15th day of the fourth month after the end of the corporation’s tax year (for most fiscal-year corporations).
Estates and Trusts (Form 1041): April 15, 2026. Extension period: 5½ months, with a deadline of September 30 for calendar-year entities.
Exempt Organizations (Form 990): May 15 for calendar-year organizations (extended deadline: November 16).
1099 Forms and W-2 Form: Filing deadlines for 2026 - January 31, 2026.
Tax payment deadline: Any tax due must be paid by April 15 to avoid penalties and interest (even if an extension is filed).

Individuals (Estimated Taxes):
Quarterly estimated tax payments are generally due on April 15, June 15, September 15, and January 15 of the following year.
C-Corp (Estimated Taxes):
Quarterly estimated tax payments are generally due on April 15, June 15, September 15, and December 15 of the following year.

Q4 Estimated Tax Payments

Please remember that 4th quarter estimated tax payments for tax year 2025 are due by January 15, 2026.

This reminder applies to:

Timely payment is important to help avoid underpayment penalties and interest.

WHITNAH CPA