The federal tax filing deadline is April 15, or the next business day when it falls on a weekend or legal holiday. An extension moves the filing deadline six months, to October 15 — and for 2025 returns that's October 15, 2026. What the extension never moves is the payment: any tax you owed was due in April, and the IRS has been adding a monthly penalty and interest on unpaid amounts since then.
If you're reading this with an extension and an unfinished return, you have until October 15. If you never requested one and haven't filed, file as soon as you can — the larger penalty is for not filing.
- April 15return and payment duenext business day if it falls on a weekend or holiday
- Oct. 15filing deadline with an extensionfor 2025 returns: October 15, 2026
- 5% / mofailure-to-file penaltyof unpaid tax, up to 25%
- 0.5% / mofailure-to-pay penaltyof unpaid tax, up to 25%, plus interest
As of October 2026 · Sources: irs.gov (When to file, Extension of time to file, Failure to file and Failure to pay penalties).
The dates that matter
- April 15Return due, any tax owed due, extension request due, Q1 estimated tax
- June 15Q2 estimated tax; filing deadline for citizens living abroad
- Sept. 15Q3 estimated tax
- Oct. 15Last day to file with an extension
- Jan. 15Q4 estimated tax for the year just ended
Each date moves to the next business day if it falls on a weekend or legal holiday. Disaster areas and combat zones get more time.
The IRS rule is mechanical: a calendar-year return is due on the 15th day of the fourth month after the year ends. A return mailed on time counts as filed on time if it's properly addressed, postmarked and in the mail by the due date.
- April 15: return due, tax due, and the last day to request an extension. It's also the first estimated tax payment for the new year.
- June 15: U.S. citizens and resident aliens living and working outside the U.S. and Puerto Rico get an automatic two-month extension to file until then, as do military members on duty abroad. Interest still runs on any tax paid after April 15.
- October 15: the end of the extended filing period.
For the return covering 2026, the rule gives Thursday, April 15, 2027. Check irs.gov for the confirmed date before you plan around it.
What an extension does — and what it doesn't
The extension is automatic — the form is literally called the Application for Automatic Extension of Time To File. You have three ways to get it, all by the April deadline:
- Pay online and mark it as an extension. Pay all or part of what you owe through your IRS Online Account, Direct Pay or EFTPS and choose extension as the reason. No form needed; keep the confirmation number.
- IRS Free File. Anyone, at any income, can use it to request an extension electronically at no cost.
- Form 4868. File it by mail, through tax software or through a tax professional.
What the extension doesn't do is give you more time to pay. The IRS asks you to estimate your total tax for the year, subtract what you've already paid through withholding and estimated payments, and pay the rest by April 15. If your estimate comes up short, you'll owe the failure-to-pay penalty and interest on the difference — but not the much larger failure-to-file penalty, as long as you file by October 15.
What it costs to miss a deadline
Two separate penalties apply, and they behave differently:
| Penalty | Rate | Cap |
|---|---|---|
| Failure to file | 5% of unpaid tax for each month or part of a month late | 25% |
| Failure to pay | 0.5% of unpaid tax for each month or part of a month | 25% |
| Failure to pay, with an approved payment plan (filed on time) | 0.25% per month | 25% |
When both apply in the same month, the filing penalty is reduced by the payment penalty, so the combined charge is 5% a month until the filing penalty maxes out after five months. If your return is more than 60 days late, there's a minimum failure-to-file penalty: for returns due after December 31, 2025, it's $525 or 100% of the unpaid tax, whichever is less. Interest comes on top.
Two points of comfort. Both penalties are percentages of unpaid tax, so if you're owed a refund, they have nothing to bite on. And the IRS can remove penalties if you show reasonable cause; interest is only reduced when the penalty is.
Estimated taxes: the other four deadlines
If you're self-employed or have income without withholding, the year has four more dates. The IRS splits the year into payment periods:
| Income earned | Payment due |
|---|---|
| January 1 – March 31 | April 15 |
| April 1 – May 31 | June 15 |
| June 1 – August 31 | September 15 |
| September 1 – December 31 | January 15 of the next year |
Underpaying a period can cost a penalty even if you end up with a refund. The freelancer paperwork guide covers the receipts and invoices that make these payments less of a guess.
Special cases
- Disaster areas: if the IRS declares relief for your area, you may get up to a year after the due date to file and pay, with no extension request needed. The IRS lists current relief on its disaster page.
- Combat zones: at least 180 days after leaving the zone to file and pay.
- State taxes: your state tax agency sets its own deadline and extension rules; check them separately.
Keeping April from becoming October
The manual method is boring and effective: one folder (paper or digital) per tax year, where every W-2, 1099, receipt and donation letter goes the day it arrives, plus calendar reminders for April 15 and, if you need them, the four estimated tax dates. The year-round tax documents guide has the full system, and how long to keep tax records tells you when you can finally shred them.
Paperlock helps with the collecting part: snap each form or receipt as it arrives, and it reads who it's from, the date and the amount, so in March you can ask show me every 1099 from last year and get the documents, not a search.
This page describes IRS rules as of October 2026 and isn't tax advice. For your own situation — a missed deadline, a payment plan, a disaster extension — check irs.gov or talk to a tax professional.