Three of the year’s big federal tax deadlines are already behind us. The fourth-quarter estimated payment for 2025 came due on January 15, the main filing deadline landed on Wednesday, April 15, and the second-quarter estimated payment for 2026 arrived on Monday, June 15. If you hit all three, you can relax for a bit. If you missed one, or you filed an extension in April, the second half of the year is where things get decided.
Here is the full 2026 tax calendar in one place: what has passed, what is still coming, and the quiet rules (like what happens when a deadline falls on a weekend) that trip people up. Every date below comes from the IRS’s own schedule, and the agency publishes the whole thing in Publication 509, Tax Calendars, if you want the official version pinned to your fridge.
What has already happened in 2026
January 15 was the due date for the final estimated tax payment on 2025 income, the payment self-employed people and retirees with untaxed income make to square up before filing. Late January brought the opening of filing season, when the IRS began accepting 2025 returns. Then April 15 did triple duty: it was the deadline to file your 2025 return or request an extension, the deadline to pay any 2025 tax you owed, and the due date for the first estimated payment on 2026 income. It was also the last day to make a 2025 contribution to an IRA.
June 15 closed out the first half. That was the second estimated payment deadline for 2026, and it was also the automatic extended filing deadline for Americans living and working abroad, who get two extra months without asking. The IRS explains both of those rules on its When to File page.
September 15: the third estimated payment
The next date that matters is Tuesday, September 15, when the third quarterly estimated payment for 2026 is due. A quick warning for anyone new to estimates: the “quarters” are not actually equal. The September payment covers income you earn from June 1 through August 31, just three months, while the January payment covers four. The IRS lays out the full schedule in its estimated tax FAQ.
Who needs to care? Generally, anyone who expects to owe $1,000 or more when they file, after subtracting withholding. That sweeps in freelancers and gig workers, landlords, retirees drawing from accounts without withholding, and anyone with meaningful investment income.
October 15: the extension wall
If you filed Form 4868 back in April, your extended deadline to file the 2025 return is Thursday, October 15. There is no extension beyond it for most people. And remember what the extension did and did not do: it gave you more time to file the paperwork, not more time to pay. Any 2025 balance was still due April 15, and interest has been building on unpaid amounts since then. The IRS covers the mechanics on its Form 4868 page. If you owe and have not paid, filing sooner stops the bleeding sooner.
January 15, 2027: the last payment on 2026 income
The final estimated payment for 2026 is due January 15, 2027. It is easy to forget because it lands after the holidays and belongs to a tax year that already feels finished. Put it on the calendar now. One useful quirk: if you file your complete 2026 return and pay everything you owe by February 1, 2027, you can skip the January estimated payment entirely.
The weekend and holiday rule
When a federal tax deadline falls on a Saturday, Sunday, or legal holiday, it rolls to the next business day. None of the remaining 2026 dates need that adjustment (September 15 is a Tuesday and October 15 is a Thursday), but the rule matters in other years and for state deadlines that follow their own calendars. Legal holidays in the District of Columbia count for this purpose, which is why Emancipation Day has nudged Tax Day in some past years.
Deadlines can move if disaster strikes
One more wrinkle worth knowing: when a federally declared disaster hits an area, the IRS routinely postpones filing and payment deadlines for everyone who lives or runs a business there, often by months. The extensions are automatic based on your address, and the agency keeps a running list on its disaster relief page. If a storm, fire, or flood has hit your county this year, check that list before you assume a date above applies to you.
A simple way to stay ahead
The pattern for the rest of 2026 is mercifully short: September 15 for estimates, October 15 for extended returns, and January 15 for the last estimated payment. If you pay estimates, consider scheduling all the remaining payments now through your IRS online account or EFTPS, so the dates cannot sneak past you. Missing an estimated payment is not catastrophic, but it does trigger an underpayment penalty that compounds quietly until you catch up. The cheapest tax move you can make this year is also the simplest one: write these three dates down where you will actually see them.
