2026 Individual Tax Calendar: Key Deadlines for the Remainder of 2026

Now that the April 15 tax deadline has passed, it’s easy to shift focus. Key tax dates continue throughout the year, and it’s important to stay aware of these deadlines to avoid penalties and plan properly.

Below is a helpful overview of key upcoming due dates for forms, payments, and other tax-related actions. Keep in mind, this isn’t a complete list, and additional deadlines may apply depending on your situation.

Take a moment to review the timeline, and reach out if you have questions or need help staying on track.

June 15

Taxpayers living outside the United States and Puerto Rico, as well as those serving in the military abroad, must file their 2025 individual income tax return (Form 1040 or Form 1040-SR) or request a four-month extension using Form 4868. Any taxes owed, including interest and penalties, should be paid by this date.

This is also the deadline to make the second installment of 2026 estimated tax payments (Form 1040-ES) if you don’t have enough tax withheld from your income.

September 15

The third installment of 2026 estimated tax payments (Form 1040-ES) is due for individuals who are not fully covered by withholding.

September 30

Trustees and executors must file a 2025 income tax return for trusts and estates (Form 1041) if a five-and-a-half-month extension was previously filed. Any outstanding taxes, along with interest and penalties, must be paid at this time.

October 15

This is the final deadline to file a 2025 individual income tax return (Form 1040 or Form 1040-SR) for those who requested an automatic six-month extension (or a four-month extension for qualifying taxpayers abroad). All taxes, interest, and penalties must be settled by this date.

It’s also the last day to make certain retirement plan contributions for 2025 or to establish a SEP plan if you filed an extension.

In addition, taxpayers who extended their filing must submit their 2025 gift tax return (Form 709) and pay any related taxes due.

December 31

Year-end planning opportunities come into focus. By this date, you can make contributions to certain employer-sponsored retirement plans for 2026.

It’s also the deadline to make annual exclusion gifts (up to $19,000 per recipient) for 2026.

And as we all know - the end of the year is the cutoff to incur expenses that may qualify as itemized deductions on your 2026 tax return, such as charitable contributions, medical expenses, and property tax payments.

Staying ahead of these deadlines can make a meaningful difference in your overall tax picture. If you’d like guidance or support with any of these items, professional assistance can help ensure everything is handled accurately and on time.