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Tax Deadlines This Month: October 2026 (and What Happens If You Miss One)
Last reviewed September 30, 2026 by Sabih Shafi, EA. This page is rewritten on the first of every month; the URL never changes. Dates are checked against IRS Publication 509 and the current form instructions.
Short answer
Thursday, October 15, 2026 is the last day to file an extended 2025 individual return (Form 1040) and an extended calendar-year C-corporation return (Form 1120). Your FBAR (FinCEN Form 114) also gets its automatic extension to October 15. The extension never extended the time to pay, so file by the 15th even if you cannot pay the balance.
October 2026 deadlines
Thursday, October 15: extended 2025 Form 1040 for anyone who filed Form 4868 in April. No further extension exists for individuals.
October 15: extended calendar-year Form 1120 for C corporations that filed Form 7004.
October 15: FBAR (FinCEN Form 114) automatic extension ends for 2025 foreign accounts over $10,000 combined.
October 15: SEP-IRA and employer solo 401(k) contributions for 2025 when the return was extended.
October 15: California Franchise Tax Board extended 2025 Form 540 (the extension to file was automatic; payment was due April 15).
October 15: monthly payroll depositors deposit September federal employment taxes.
Monday, November 2: Form 941 for the third quarter (October 31 falls on a Saturday); November 10 if every deposit for the quarter was made on time.
Monday, November 2: Form 720 federal excise tax for the third quarter.
Coming up
Tuesday, December 15: fourth-quarter estimated tax for calendar-year corporations.
Friday, January 15, 2027: fourth-quarter 2026 estimated tax for individuals (Form 1040-ES).
Monday, February 1, 2027: Forms W-2 and 1099-NEC to recipients and to the SSA and IRS (January 31 is a Sunday).
What happens if you miss October 15
The failure-to-file penalty starts the next day at 5 percent of the unpaid tax per month or part of a month, capped at 25 percent, on top of the late-payment penalty and daily interest. If you are owed a refund there is no late-filing penalty, but you have three years to claim it before it belongs to the Treasury. Filing late is still far cheaper than not filing: an unfiled return can become a Substitute for Return with no deductions and the least favorable filing status. The full math, with a worked example, is in our October 15 extension deadline guide.
If you cannot pay
File anyway and pay what you can with the return. Filing stops the large penalty; the balance is a separate conversation. The payment paths are a short-term plan, an installment agreement, currently-not-collectible status, or an Offer in Compromise when the numbers support it. Penalties already charged can be reviewed for First-Time Abatement or reasonable cause through penalty abatement.
Frequently Asked Questions
Can I get another extension after October 15?
No. For individual returns the six-month extension to October 15 is the maximum. After that the only option is to file as soon as possible to stop the failure-to-file penalty.
Did the extension give me more time to pay?
No. An extension only extends the time to file. Tax owed for 2025 was due April 15, 2026, and the late-payment penalty plus interest has been running on any unpaid balance since then.
Does my federal extension cover my state return?
Not automatically. Most states grant their own extension to file but still charge their own late-payment penalties; California's Franchise Tax Board is one example.
What if I am due a refund and miss October 15?
There is no late-filing penalty when no tax is owed, but you must file within three years of the original deadline to receive the refund.
Related Reading
Need it filed this week?
This page is general information, not individual tax advice. If a deadline above applies to you and the return is not done, book a free 20-minute review with an Enrolled Agent or call or text us directly.
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