Key Dates for Tax Extension Deadlines

(This article was last updated on September 16, 2026.)

Tax deadlines can be easy to lose track of, especially when extensions, estimated tax payments, and different business filing dates are involved. Knowing which deadlines apply to you can help you stay compliant, avoid unnecessary penalties, and give yourself enough time to prepare an accurate return.

If you need more time to file, a tax extension can help. But there’s one important distinction every taxpayer should understand: an extension gives you more time to file your return. However, it does not give you more time to pay your taxes.

Any tax you expect to owe generally must still be paid by the original tax deadline. If you don’t pay enough by that date, interest and potential late-payment penalties may apply even if you filed an extension.

Find out what small business owners need to know about tax extensions →

Key tax extension deadlines

The deadline that applies to you depends on the type of return you’re filing. The following dates generally apply to 2025 tax returns filed during 2026.

Individual taxpayers

• April 15, 2026: Deadline to file most individual federal income tax returns (Form 1040) for tax year 2025 and pay taxes owed.
• October 15, 2026: Extended filing deadline for taxpayers who properly requested an extension by April 15.

Partnerships and S corporations

• March 16, 2026: Filing deadline for calendar-year partnerships (Form 1065) and S corporations (Form 1120-S). Because March 15 fell on a Sunday in 2026, the deadline moved to the next business day.
• September 15, 2026: Extended filing deadline for calendar-year partnerships and S corporations that received an extension.

C corporations

• April 15, 2026: Filing deadline for most calendar-year C corporations (Form 1120).
• October 15, 2026: Extended filing deadline for calendar-year C corporations that received an extension.

Keep in mind that businesses operating on a fiscal year rather than a calendar year may have different filing deadlines.

Estimated tax payment deadlines

A filing extension does not change your estimated tax payment schedule. Individuals and certain business owners who are required to make estimated tax payments should keep these 2026 deadlines in mind:

• April 15, 2026: First quarter payment
• June 15, 2026: Second quarter payment
• September 15, 2026: Third quarter payment
• January 15, 2027: Fourth quarter payment for the 2026 tax year

Estimated taxes are generally used to pay income tax and other taxes throughout the year when enough tax isn’t being withheld from your income. Depending on your circumstances, missing or underpaying estimated tax payments can result in an underpayment penalty.

Tax deadlines for nonprofit organizations

For many tax-exempt organizations operating on a calendar year:

• May 15, 2026: Deadline to file the applicable Form 990-series return for the 2025 calendar year.
• November 15, 2026: Extended deadline for organizations that properly requested an extension. Because November 15 falls on a Sunday in 2026, the deadline moves to the next business day.

Different rules may apply depending on the organization’s tax year and the specific Form 990-series return being filed.

How to file a tax extension

For most taxpayers, requesting an extension is relatively straightforward.

• Individuals can file Form 4868. IRS Form 4868 can generally be filed electronically or by mail by the original filing deadline. A timely request provides an automatic six-month extension to file your federal individual income tax return.
• Businesses generally use Form 7004. Eligible business entities can use Form 7004 to request an automatic extension for many business income tax, information, and other returns. The form must generally be submitted by the return’s original due date.

Remember, requesting an extension doesn’t postpone your tax bill. You should estimate the amount you expect to owe and pay as much as possible by the original payment deadline.

How Vyde supports tax extensions

If you need a tax extension, Vyde can help you understand the deadlines that apply to your business, prepare the necessary extension paperwork, and determine what information is still needed to complete your return.

But filing the extension is only part of the process. Vyde can also help you stay organized during the extension period, prepare your return, understand potential tax obligations, and plan ahead for future estimated tax payments and filing deadlines.

An extension can provide valuable breathing room when you need additional time to prepare an accurate return. The key is to use that extra time wisely and remember that an extension to file is not an extension to pay.

With year-round bookkeeping, tax preparation, and tax strategy support, Vyde helps small business owners stay on top of their finances and prepare for tax deadlines before they arrive.