2021 Tax Calendar Deadlines

January 15th, 2021

• Deposit Federal payroll taxes for December 2020 if a monthly depositor 

January 6, 2021

• Final December 2020 Quarter-Monthly Withholding and Sales Tax Payment

January 31, 2021

• St Louis City 4th Quarter 2020 Form W-10 and P-10 Due

January 31, 2021

• St Louis City Annual W-3 reconciliation due

February 1, 2021

• 1099 NEC and 1099 MISC to vendors and the IRS
• W-3 and W2 forms to employees and the IRS
• File Form 940, 941, 943 payroll tax returns and make payments due
• Sales/Use tax returns and payments due

February 16, 2021 

• Deposit Federal payroll taxes for January if a monthly depositor

February 1, 2021

• 2020 Form MO W-3 due

February 1, 2021 

• 2020 Annual, Monthly, and Quarterly Withholding, Sales and Use, Tire and Battery Fee Return

February 16, 2021

• Monthly Withholding Tax Return

February 22, 2021 

• Monthly Sales and Use Tax Return

February 15, 2021

• Form W-11 Monthly Withholding for January due

March 15, 2021

• Tax returns due for S-Corporations and multi-member LLCs/Partnerships
• Deposit Federal payroll taxes for February if a monthly depositor

March 15, 2021 

• Calendar Year Cooperatives (Form MO-1120) with an
• Automatic Extension
• Monthly Withholding Tax Return

March 22, 2021

• Monthly Sales and Use Tax Return
• Monthly Tire and Battery Fee Return

March 1, 2021

• St. Louis County Business personal property declaration due 

March 1, 2021 

• St. Charles County Business personal property declaration due 

March 1, 2021 

• St Louis City Annual Business 1099 Report (Form E-6) 

March 15, 2021 

• Form W-11 Monthly Withholding for February due

April 15th, 2021

• Tax returns due for C-Corporations, Sole Proprietors, and Single-Member LLCs as well as personal 1040 returns.
• Pay 1st installment of 2021 estimated tax

April 15th, 2021

• Deposit Federal payroll taxes for March if a monthly depositor 

April 30th, 2021 

• File 1st Quarter Form 941

April 15, 2021

• Annual Business and Individual Consumer’s Use Tax Return
• Form MO-1120ES
• Form MO-1040-ES
• Form MO – 1065
• Form MO – 1120
• Form MO – 1120S
• Form MO – 1040V

April 30, 2021

• Monthly and Quarterly Withholding, Sales and Use, and Tire and Battery Fee

April 1, 2021 

• St. Louis City Business personal property declaration due

April 15, 2021 

• St Louis City Form E-234 Return is due

April 30, 2021 

• St Louis City 1st Quarter 2021 Form W-10 and P-10 Due

May 15, 2021

• St Louis City Form W-11 Monthly Withholding for April due

May 17, 2021

• Forms MO-1120 and MO-7004 for those filing Federal Form 990-T
• Monthly Withholding Tax Return

May 20, 2021 

• Monthly Sales and Use Tax Return

May 15, 2021 

• Form W-11 Monthly Withholding for April due

June 15th, 2021

• Individuals and Corporations – Pay the 2nd installment of 2021 estimated tax

June 15th, 2021 

• Deposit Federal payroll taxes for May if a monthly depositor

June 15, 2021

• Form MO-1040ES
• Form MO – 1120ES
• Monthly Withholding Tax Return

June 21, 2021

• Monthly Sales and Use Tax Return

June 15, 2021

• St Louis City Form W-11 Monthly Withholding for May due

July 15th, 2021 

• Deposit Federal payroll taxes for June if a monthly depositor

July 6, 2021 

• Quarter-Monthly Withholding and Sales Tax Payment

July 31, 2021

• St Louis City 2nd Quarter 2021 Form W-10 and P-10 Due

August 2nd, 2021

• File 2nd Quarter Form 941

August 2nd, 2021 

• Deposit FUTA owed through June if more than $500

August 16th, 2021 

• Deposit Federal payroll taxes for July if a monthly depositor

August 2, 2021

• Monthly and Quarterly Withholding, Sales and Use, and Tire and Battery Fee Return

August 15, 2021

• St Louis City Form W-11 Monthly Withholding for  July due

September 15th, 2021

• Deposit Federal payroll taxes for August if a monthly depositor 

September 15th, 2021 

• Individuals and Corporations – Pay the 3rd installment of 2021 estimated tax

September 15th, 2021

• S Corporation and Partnership returns due if a 6-month extension was requested.

September 15, 2021

• Form MO-1040ES
• Form MO – 1120ES
• Monthly Withholding Tax Return

September 20, 2021

• Monthly Sales and Use Tax Return
• Monthly Tire and Battery Fee Return

September 15, 2021

• St Louis City Form W-11 Monthly Withholding for August due

October 15th, 2021 

Deposit Federal payroll taxes for September if a monthly depositor 

October 15th, 2021 

• Individuals and Corporation returns due if a 6-month extension was requested

October 15, 2021 

• Form MO-1040 with Extension

October 31, 2021

• St Louis City 3rd Quarter 2021 Form W-10 and P-10 Due

November 1st, 2021

• File 3rd Quarter Form 941

November 1st, 2021 

• Deposit FUTA owed through September if more than $500

November 15th, 2021

• Deposit Federal payroll taxes for October if a monthly depositor

November 1, 2021

• Monthly and Quarterly Withholding, Sales and Use, and Tire and Battery Fee

November 15, 2021

• Form MO – 1120 for those filing Federal Form 990-T with extension
• Monthly Withholding Tax Return

November 22, 2021    

• Monthly Sales and Use Tax Return
• Monthly Tire and Battery Fee Return

December 15th, 2021 

• Deposit Federal payroll taxes for November if a monthly depositor 

December 15th, 2021 

• Corporations – Pay the 4th installment of 2021 estimated tax

December 15, 2021

• Form MO – 1120ES
• Monthly Withholding Tax Return

December 20, 2021

• Monthly Sales and Use Tax Return
• Monthly Tire and Battery Fee Return