Upcoming Tax Deadlines: What's Next After August 2026

Tax season doesn't end in April. If you filed an extension, make estimated payments, or run a business, there are several important deadlines still ahead this year. Here's every one coming up, starting from where we are now in August 2026.

DEADLINES AT A GLANCE

Date	What's Due
Sept 15, 2026	Q3 2026 estimated tax payment (individuals & calendar-year corporations)
Sept 15, 2026	Extended deadline: 2025 Partnership (1065) & S-Corp (1120-S) returns
Oct 15, 2026	Extended deadline: 2025 individual returns (Form 1040)
Oct 15, 2026	Extended deadline: 2025 C-Corporation returns (Form 1120)
Oct 31, 2026	Q3 Form 941 payroll tax return (employers)
Nov 16, 2026	Extended deadline: 2025 Louisiana individual state return
Nov 16, 2026	Extended federal deadline: calendar-year nonprofit returns (Form 990)
Jan 15, 2027	Q4 2026 estimated tax payment

EXTENSION TO FILE IS NOT AN EXTENSION TO PAY

If you filed Form 4868 back in April, October 15 is your deadline to actually file — but any tax you owed was still due back in April, and interest has been accruing on the unpaid balance since then. The same is true for the September 15 business return deadline: filing late without an extension carries a much steeper penalty than paying late.

ONGOING DEADLINES WORTH REMEMBERING

• Louisiana parish sales tax returns are generally due by the 20th of the month following the reporting period, every month or quarter depending on your filing frequency.

• Employers on a monthly deposit schedule have ongoing payroll tax deposit deadlines throughout the fall.

DON'T WAIT UNTIL THE DEADLINE

Deadlines can shift for taxpayers in federally declared disaster areas, so always confirm your specific date if your area has had a recent disaster declaration. This article is general information and not a substitute for advice on your specific situation. If you have a deadline coming up and aren't sure what you need to file, call our office at 504-315-2667.