Important Tax Filing Deadlines for 2026

Ever missed a tax deadline and faced penalties? You're not alone—thousands of taxpayers pay avoidable late fees every year simply because they lost track of important tax dates.

The problem is that tax deadlines aren't all in April—there are quarterly payments, extension dates, retirement contribution cutoffs, and business filing deadlines scattered throughout the year. Missing any of these can trigger penalties, interest charges, and unnecessary stress.

This comprehensive guide provides all major tax deadlines for 2026 with specific dates for individual filers, self-employed workers, businesses, and retirement accounts. You'll know exactly when every payment and filing is due so you never miss another deadline.

Key Individual Tax Deadlines

January 15, 2026: Fourth quarter estimated tax payment for 2023 is due. If you're self-employed or have income without withholding, this payment covers September through December 2023.

January 31, 2026: Deadline for employers to provide W-2 forms to employees and for businesses to send 1099 forms to contractors and individuals. If you haven't received these by early February, contact the issuer.

April 15, 2026: The most important tax deadline—your 2023 tax return is due. This is also the deadline for first quarter 2026 estimated tax payments and the last day to contribute to IRAs for 2023. If April 15 falls on a weekend or holiday, the deadline moves to the next business day.

Quarterly Estimated Tax Payment Dates

If you're self-employed or have income without withholding, mark these quarterly payment dates:

April 15, 2026: First quarter payment (January 1 - March 31)

June 17, 2026: Second quarter payment (April 1 - May 31)

September 16, 2026: Third quarter payment (June 1 - August 31)

January 15, 2026: Fourth quarter payment (September 1 - December 31)

Set reminders for these dates well in advance. Late payments incur penalties and interest, even if you eventually pay the full amount owed.

Extension Deadlines

April 15, 2026: Deadline to file Form 4868 to request an automatic six-month extension. This extends your filing deadline to October 15, 2026, but does not extend the payment deadline—you must still estimate and pay any taxes owed by April 15 to avoid penalties.

October 15, 2026: Absolute final deadline to file your 2023 tax return if you filed for an extension. There are no further extensions available except in rare circumstances like disasters or military service.

Business Tax Deadlines

March 15, 2026: S-Corporations and partnerships must file Form 1120-S or Form 1065. These entities provide K-1 forms to owners showing their share of income, which owners need to file their personal returns.

April 15, 2026: C-Corporations with calendar year-ends must file Form 1120. Single-member LLCs and sole proprietors report business income on Schedule C attached to their personal tax returns, due April 15.

Retirement Account Deadlines

April 15, 2026: Last day to make IRA contributions for 2023. Traditional and Roth IRA contributions for the previous tax year can be made up until the tax filing deadline, even if you file for an extension.

December 31, 2026: Deadline for most retirement account contributions for 2026, including 401(k), 403(b), and HSA contributions. Unlike IRAs, these must be made by year-end, not the following tax filing deadline.

Other Important Dates

December 31, 2026: Deadline for tax-loss harvesting, required minimum distributions from retirement accounts, and charitable donations you want to claim on your 2026 return. Donations and transactions must be completed by year-end to count for that tax year.

Throughout the year: Keep track of expenses for deductions, save receipts for charitable donations, and maintain mileage logs for business use. Good record-keeping throughout the year makes tax time much easier.

Penalties for Missing Deadlines

Missing deadlines can be costly. The failure-to-file penalty is 5% of unpaid taxes for each month your return is late, up to 25%. The failure-to-pay penalty is 0.5% per month. Interest accrues on unpaid taxes from the original due date.

If you can't pay your full tax bill by the deadline, file your return anyway to avoid the higher failure-to-file penalty. You can arrange a payment plan with the IRS to pay over time.

Conclusion

Staying organized and aware of tax deadlines helps you avoid penalties and manage your tax obligations smoothly. Set calendar reminders for these important dates, especially quarterly payment deadlines if you're self-employed. When in doubt, file for an extension—but remember to pay estimated taxes by the original deadline.

Use our Tax Estimator to calculate your payments and stay on track throughout the year.

Frequently Asked Questions