Tax Deadlines
The dates that matter for a Texas small business, federal and state together, with what each one actually applies to.
15 October 2026 is the deadline for extended individual returns (Form 1040 and 1040-SR) for calendar-year taxpayers. 20 October 2026 is the Texas sales tax due date for quarterly filers covering July–September.
Extension season, 2026
| Date | What is due |
|---|---|
| 15 Sep 2026 | Extended partnership (Form 1065) and S-corporation (Form 1120-S) returns; third-quarter estimated payment |
| 30 Sep 2026 | Extended trust and estate returns (Form 1041) — not a service we provide |
| 15 Oct 2026 | Extended individual returns (Form 1040 / 1040-SR) |
| 20 Oct 2026 | Texas sales tax, quarterly filers, July–September period |
| 15 Jan 2027 | Fourth-quarter estimated payment for 2026 |
| 20 Jan 2027 | Texas sales tax, quarterly and annual filers |
| 15 May 2027 | Texas franchise tax annual report, including the PIR or OIR |
Dates that fall on a weekend or holiday generally move to the next business day. We prepare returns for LLCs, S-corporations, partnerships, sole proprietors and individuals; we do not prepare C-corporation, trust or estate returns.
An extension to file was never an extension to pay
This is the single most expensive misunderstanding in the calendar. Filing an extension moved your paperwork deadline to October. It did not move the payment deadline, which was in April. Anything unpaid has been accruing interest and penalty since then.
Why filing late costs so much more than paying late
| Penalty | Rate | Cap |
|---|---|---|
| Failure to file | 5% of tax owed per month or part month | 25% |
| Failure to pay | 0.5% of unpaid tax per month or part month | 25% |
Filing late costs ten times per month what paying late costs. If you cannot pay, file anyway — it is the cheapest decision available to you. If a return is more than 60 days late the minimum failure-to-file penalty is $525 for 2026 returns, or 100% of the tax owed if that is less.
The failure-to-pay rate rises to 1% per month once the IRS issues a notice of intent to levy and ten days pass. It drops to 0.25% per month while an approved installment agreement is in place. Interest runs on top at 7% per year, compounded daily for individuals in the fourth quarter of 2026.
Behind on more than one year?
See personal returns and business returns — we file open years in order so each one starts from the right position.
Federal penalty and interest figures per the IRS: Topic no. 653, IRS notices and bills, penalties and interest charges and interest rates for the fourth quarter of 2026. Texas dates per the Texas Comptroller. Verified September 2026 — confirm before relying on any date.
Not sure which of these apply to you?
Tell us your entity type and how you file, and we will tell you which dates are yours — and handle them if you would rather not.
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