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Important tax due dates for 2021

Written by Kristen Grau on Jan 07, 2021 | Last updated on Sep 9, 2021
Reviewed by Sean DiMercurio CPA CGMA

Keep track of the most important federal and Florida tax deadlines this year.

Keeping track of tax deadlines throughout the year can protect your business from late penalties and save you money.

That’s why we put all the deadlines you likely need to know in one place. Reviewing these deadlines on a monthly or quarterly basis can help you keep track of estimated tax payment due dates, tax extension deadlines and more.

Several Florida due dates are included here. If you live in another state, stay on top of its own due dates. You can face penalties for missing state deadlines, just like you can with federal deadlines.

January 2021

February 2021

March 2021

April 2021

May 2021

June 2021

July 2021

  • July 31 | Annual return/report of employee benefit plan (Form 5500)
  • July 31 |  Second quarter payroll taxes due (Form RT-6)

August 2021

  • No due dates

September 2021

  • September 15 | Third quarter estimated tax (Form 1040-ES) due (learn more)
  • September 15 | S corporation income tax return extended due date (Form 1120S)
  • September 15 | Partnership income tax return extended due date (Form 1065)
  • September 30 | Trust income tax return extended due date (Form 1041)

October 2021

  • October 15 | Individual income tax return extended due date (Form 1040)
  • October 15 | Corporation income tax return extended due date (Form 1120)
  • October 31 | Third quarter payroll taxes due (Form RT-6)

November 2021

  • November 15 | Nonprofit income tax return extended due date (Form 990)

December 2021

  • No due dates

The bottom line

With so many federal and state tax deadlines for small business owners throughout the year, it’s easy to lose track of all of them. This calendar is designed to help you never miss a deadline — and never pay a late penalty.


Still worried about missing a deadline or filling out a form incorrectly? Talk with a DiMercurio Advisors team member today for free to learn how we could help.

Sean DiMercurio CPA CGMA

Sean DiMercurio CPA CGMA

Sean is Orlando’s most entertaining Certified Public Accountant and firmly believes ice cream can solve any problem.