Be aware that, in response to the COVID-19 pandemic, last year the U.S. Treasury and IRS postponed many 2020 due dates. As of this writing, no postponements of 2021 due dates are expected, but it's possible that could change.

March 1

Businesses must file Form 1098, Form 1099 (other than those with a February 1 or February 16 deadline) and Form W-2G and transmittal Form 1096 for interest, dividends and miscellaneous payments made during 2020. (Electronic filers can defer filing to March 31.)

March 10

Individuals need to report February tip income of $20 or more to employers (Form 4070).

March 15

Calendar-year S corporations must file a 2020 income tax return (Form 1120S) or file for an automatic six-month extension (Form 7004), and pay any tax due.

Calendar-year partnerships need to file a 2020 income tax return (Form 1065 or Form 1065-B) or request an automatic six-month extension (Form 7004).

March 31

Employers must electronically file 2020 Form 1097, Form 1098, Form 1099 (other than those with an earlier deadline) and Form W-2G.

April 12

Individuals need to report March tip income of $20 or more to employers (Form 4070).

April 15

Individuals must file for an automatic six-month extension (Form 4868) and pay any tax due. (See June 15 for an exception for certain taxpayers.)

Self-employed individuals need to pay the first installment of 2021 estimated taxes, if not paying income tax through withholding (Form 1040-ES).

This is the last day to make 2020 contributions to a traditional IRA or Roth IRA (even if a 2020 income tax return extension is filed).

This is the last day to make 2020 contributions to a SEP or certain other retirement plans (unless a 2020 income tax return extension is filed).

Individuals must file a 2020 gift tax return (Form 709) or file for an automatic six-month extension (Form 8892) and pay any gift tax due. They need to file for an automatic six-month extension (Form 4868) to extend both Form 1040 and, if no gift tax is due, Form 709.

Household employers must file Schedule H, if wages paid equal $2,200 or more in 2020 and Form 1040 isn't required to be filed. For those filing Form 1040, Schedule H is to be submitted with the return and is thus extended to the due date of the return.

Trusts and estates need to file an income tax return for the 2020 calendar year (Form 1041) or file for an automatic five-and-a-half month extension to October 1 (Form 7004), and pay any income tax due.

Calendar-year corporations must file a 2020 income tax return (Form 1120) or file for an automatic six-month extension (Form 7004), and pay any tax due.

Calendar-year corporations need to pay the first installment of 2021 estimated income taxes.

April 30

Employers must report income tax withholding and FICA taxes for first quarter 2021 (Form 941) and pay any tax due.

May 10

Individuals need to report April tip income of $20 or more to employers (Form 4070).

Employers must report income tax withholding and FICA taxes for first quarter 2021 (Form 941), if you deposited on time and in full all of the associated taxes due.

May 17

Exempt organizations need to file a 2020 calendar-year information return (Form 990, Form 990-EZ or Form 990-PF) or filing for an automatic six-month extension (Form 8868) and pay any tax due.

Small exempt organizations with gross receipts normally of $50,000 or less must file a 2020 e-Postcard (Form 990-N), if not filing Form 990 or Form 990-EZ.

June 10

Individuals need to report May tip income of $20 or more to employers (Form 4070).

June 15

Individuals must file a 2020 individual income tax return (Form 1040 or Form 1040-SR) or file for a four-month extension (Form 4868), and pay any tax and interest due if you live outside the United States.

Individuals need to pay the second installment of 2021 estimated taxes, if not paying income tax through withholding (Form 1040-ES).

Calendar-year corporations must pay the second installment of 2021 estimated income taxes.

July 12

Individuals need to report June tip income of $20 or more to employers (Form 4070).

August 2

Employers must report income tax withholding and FICA taxes for second quarter 2021 (Form 941) and pay any tax due.

Employers need to file a 2020 calendar-year retirement plan report (Form 5500 or Form 5500-EZ) or request an extension.

August 10

Individuals need to report July tip income of $20 or more to employers (Form 4070).

Employers must report income tax withholding and FICA taxes for second quarter 2021 (Form 941), if you deposited on time and in full all of the associated taxes due.

September 10

Individuals need to report August tip income of $20 or more to employers (Form 4070).

September 15

Individuals must pay the third installment of 2021 estimated taxes, if not paying income tax through withholding (Form 1040-ES).

Calendar-year corporations need to pay the third installment of 2021 estimated income taxes.

Calendar-year S corporations must file a 2020 income tax return (Form 1120S) and pay any tax, interest and penalties due, if an automatic six-month extension was filed.

Calendar-year S corporations need to make 2020 contributions for certain employer-sponsored retirement plans, if an automatic six-month extension was filed.

Calendar-year partnerships must file a 2020 income tax return (Form 1065 or Form 1065-B), if an automatic six-month extension was filed.

October 1

Trusts and estates need to file an income tax return for the 2020 calendar year (Form 1041) and pay any tax, interest and penalties due, if an automatic five-and-a-half month extension was filed.

Employers must establish a SIMPLE or a Safe-Harbor 401(k) plan for 2020 by this date, except in certain circumstances.

October 12

Individuals need to report September tip income of $20 or more to employers (Form 4070).

October 15

Individuals must file a 2020 income tax return (Form 1040 or Form 1040-SR) and pay any tax, interest and penalties due, if an automatic six-month extension was filed (or if an automatic four-month extension was filed by a taxpayer living outside the United States).

Individuals need to make 2020 contributions for certain existing retirement plans or establish and contribute to a SEP for 2020, if an automatic six-month extension was filed.

Individuals must file a 2020 gift tax return (Form 709) and pay any tax, interest and penalties due, if an automatic six-month extension was filed.

Calendar-year C corporations need to file a 2020 income tax return (Form 1120) and pay any tax, interest and penalties due, if an automatic six-month extension was filed.

Calendar-year C corporations must make 2020 contributions for certain employer-sponsored retirement plans, if an automatic six-month extension was filed.

November 1

Employers need to report income tax withholding and FICA taxes for third quarter 2021 (Form 941) and pay any tax due.

November 10

Individuals must report October tip income of $20 or more to employers (Form 4070).

Employers need to report income tax withholding and FICA taxes for third quarter 2021 (Form 941), if you deposited on time and in full all of the associated taxes due.

November 15

Exempt organizations must file a 2020 calendar-year information return (Form 990, Form 990-EZ or Form 990-PF) and pay any tax, interest and penalties due, if a six-month extension was previously filed.

December 10

Individuals need to report November tip income of $20 or more to employers (Form 4070).

December 15

Calendar-year corporations must pay the fourth installment of 2021 estimated income taxes.

December 31

Employers need to establish a retirement plan for 2021 - generally other than a SIMPLE, a Safe-Harbor 401(k) or a SEP.