Tax Deadlines

2026 Tax Calendar: Key IRS Deadlines

Staying organized with IRS deadlines is essential to avoid penalties and interest. This comprehensive 2026 tax calendar covers filing dates, estimated tax payments, business deadlines, and extensions for individuals and businesses.

📅 January 5, 2026 • ⏱ 9 min read • 📝 By TaxWizard USA

Missing an IRS deadline can result in costly penalties, interest charges, and unnecessary stress. Whether you're a salaried employee, freelancer, business owner, or investor, knowing when taxes are due allows you to plan ahead and stay compliant.

This guide outlines the most important federal tax deadlines for the 2026 tax year, including estimated payments, extension dates, and business filing requirements.

Major 2026 IRS Tax Deadlines

  • January 15, 2026: Fourth-quarter 2025 estimated tax payment due
  • March 16, 2026: S-Corporation and Partnership returns due (Form 1120-S, 1065)
  • April 15, 2026: Individual tax returns due (Form 1040)
  • April 15, 2026: First-quarter estimated tax payment due
  • June 15, 2026: Second-quarter estimated tax payment due
  • September 15, 2026: Third-quarter estimated tax payment due
  • October 15, 2026: Extended individual tax return deadline

Month-by-Month 2026 Tax Calendar

January: Final estimated payment for the previous year is due. Employers must send W-2s and 1099s by January 31.

March: Business owners with partnerships or S-corps must file or request extensions by mid-March.

April: The most critical month for taxpayers. Individual returns, first estimated payments, and C-corporate returns are due.

June & September: Estimated tax payments for self-employed individuals and investors are due.

October: Final deadline for those who filed extensions. No extension applies to taxes owed.

Penalties for Missing Tax Deadlines

The IRS charges penalties for both late filing and late payment. The failure-to-file penalty can reach 5% per month, while interest accrues daily on unpaid balances.

Filing on time—even if you can’t pay—reduces penalties significantly. Payment plans and hardship options are available.

Frequently Asked Questions (FAQ)

Missing a deadline can result in penalties and interest. Filing as soon as possible reduces the total cost.

Yes. Filing Form 4868 grants a 6-month extension, but taxes owed must still be paid by April 15.

If you expect to owe $1,000 or more and lack sufficient withholding, estimated payments are required.

Many states follow federal deadlines, but not all. Always check your specific state’s tax authority.