The 2026 tax calendar at a glance
| Date | Deadline |
|---|---|
| January 15, 2026 | Q4 2025 estimated tax payment |
| Late January 2026 | IRS begins accepting 2025 returns; W-2s and most 1099s due to you by Feb 2 |
| April 15, 2026 | 2025 federal return & payment due · extension requests (Form 4868) · Q1 2026 estimate · last day for 2025 IRA/HSA contributions |
| June 15, 2026 | Q2 2026 estimate · automatic deadline for U.S. citizens abroad |
| September 15, 2026 | Q3 2026 estimate · extended partnership/S-corp returns |
| October 15, 2026 | Extended 2025 individual returns due |
| January 15, 2027 | Q4 2026 estimated tax payment |
The extension trap: more time to file ≠ more time to pay
Form 4868 gives anyone an automatic six-month filing extension to October 15 — no reason needed. But your payment was still due April 15. Interest plus the 0.5%/month late-payment penalty run on any unpaid balance from April 16. The right move when you can't finish your return: estimate your liability (our refund estimator gets you close), pay that amount with the extension, and square up when you file.
What missing the deadline actually costs
- Failure to file: 5% of unpaid tax per month, up to 25% — ten times harsher than the payment penalty. Even if you can't pay a cent, always file or extend by April 15.
- Failure to pay: 0.5% per month (capped at 25%) plus interest at the federal rate, compounded daily.
- Both at once: the combined monthly hit is capped at 5%; minimum failure-to-file penalty after 60 days is $510 (2025 returns) or 100% of tax due, whichever is smaller.
- Owed a refund? No penalty at all for filing late — but you forfeit the refund entirely if you don't claim it within three years.
Quarterly estimates: who actually has to pay them
If you expect to owe $1,000+ after withholding — typical for freelancers, landlords, and investors — you're on the quarterly schedule above. The clean safe harbor: pay 100% of last year's total tax (110% if AGI exceeded $150,000) in four equal installments and no penalty can apply regardless of this year's income. Run the numbers with the self-employment tax calculator.
Special situations
- Disaster areas: the IRS automatically extends deadlines for federally declared disaster zones — check IRS.gov if your county was affected.
- Military in combat zones: at least 180 days after leaving the zone for virtually all tax actions.
- Americans abroad: automatic two-month extension to June 15, but interest still runs from April 15.
- Amended returns: generally three years from the original deadline to claim a refund via Form 1040-X.