An extension is not a payment plan
Form 4868 and Form 7004 extend the time to file, never the time to pay. Interest runs from the original due date on anything unpaid, and the failure-to-pay penalty accrues alongside it.
Resources
Tax calendar
Federal and Florida deadlines from now through the 2026 filing cycle. Filter by entity type to see only what applies to you.
Confirm before you rely on these. Deadlines move to the next business day when they fall on a weekend or federal holiday, and the IRS regularly postpones them in federally declared disaster areas, which affects Florida more often than most states. Fiscal-year filers have different dates entirely. Treat this as a planning aid, not authority.
| Date | Deadline | Detail |
|---|---|---|
| 15 Sep 2026 Tue |
Q3 2026 estimated tax payment | Third-quarter estimates due for individuals, trusts and calendar-year C corporations. |
| 15 Sep 2026 Tue |
Extended 2025 Forms 1120-S and 1065 | Final deadline for extended S corporation and partnership returns. K-1s must reach owners. |
| 15 Oct 2026 Thu |
Extended 2025 Form 1040 | Final deadline for extended individual returns. No further extension is available. |
| 15 Oct 2026 Thu |
Extended 2025 Form 1120 | Final deadline for extended calendar-year C corporation returns. |
| 15 Oct 2026 Thu |
Extended FBAR for 2025 | FinCEN Form 114 final deadline after the automatic extension. |
| 2 Nov 2026 Mon |
Q3 2026 Form 941 | Quarterly federal payroll return, and Florida RT-6 reemployment tax. Moved from Saturday 31 October. |
| 15 Dec 2026 Tue |
Q4 2026 C corporation estimate | Fourth-quarter estimated payment for calendar-year C corporations. |
| 31 Dec 2026 Thu |
Year-end planning cut-off | Assets must be placed in service, most plans adopted, gifts made and distributions taken by this date. |
| 15 Jan 2027 Fri |
Q4 2026 estimated tax payment | Final individual estimate for the 2026 tax year. |
| 1 Feb 2027 Mon |
Forms W-2, W-3 and 1099-NEC | Employee and contractor statements due to recipients and to the IRS or SSA. Q4 Form 941 and annual Form 940 also due. Moved from Sunday 31 January. |
| 1 Mar 2027 Mon |
Paper filing of other 1099 forms | Paper information returns other than 1099-NEC. Moved from Sunday 28 February. |
| 15 Mar 2027 Mon |
2026 Forms 1120-S and 1065 | S corporation and partnership returns due, with K-1s to owners. Form 7004 extends filing by six months, not payment. |
| 15 Mar 2027 Mon |
Form 2553 S-election for 2027 | Deadline to elect S corporation status effective for the 2027 tax year. |
| 31 Mar 2027 Wed |
Electronic filing of 1099 and 1098 forms | Electronic filing deadline for information returns other than 1099-NEC. |
| 1 Apr 2027 Thu |
Florida tangible personal property return | Form DR-405 to the county property appraiser. The exemption is lost entirely if the return is filed late. |
| 15 Apr 2027 Thu |
2026 Form 1040 and Q1 2027 estimate | Individual returns due, plus the first 2027 estimate. Also the deadline for 2026 IRA and HSA contributions. |
| 15 Apr 2027 Thu |
2026 Form 1120 and Q1 estimate | Calendar-year C corporation return and first quarterly estimate. |
| 15 Apr 2027 Thu |
FBAR for 2026 | FinCEN Form 114, with an automatic extension to 15 October that requires no request. |
| 30 Apr 2027 Fri |
Q1 2027 Form 941 and Florida RT-6 | Quarterly federal payroll return and Florida reemployment tax return. |
| 1 May 2027 Sat |
Florida Form F-1120 and annual report | Florida corporate income tax return for calendar-year filers, and the Sunbiz annual report. Confirm the business-day adjustment. |
| 17 May 2027 Mon |
Form 990 series | Annual return for calendar-year exempt organizations. Moved from Saturday 15 May. |
| 15 Jun 2027 Tue |
Q2 2027 estimate | Second individual estimate, and the automatic filing deadline for US citizens living abroad. |
| Monthly n/a |
Florida sales and use tax (DR-15) | Due on the 1st of the month following the collection period and late after the 20th. Filing frequency depends on your annual tax collected. |
No deadlines match that filter in this period.
Safe harbor beats precision
Paying 100% of last year's tax (110% above the AGI threshold) eliminates the underpayment penalty even if this year turns out much larger. It is the cheapest insurance in the code.
Payroll deposits are the sharp edge
Deposit penalties escalate to 15%, and unremitted withholding can be assessed personally under Section 6672. Of every deadline on this page, these are the ones to never miss.