Tax Deadline Calendar — Important Tax Dates For 2021

With tax season just around the corner, now is a great time to take a look at all the main tax dates for 2021.

This resource offers a monthly breakdown of key tax dates in 2021. Use it to plan ahead. And make sure that you don't get caught off guard — often leading to penalties.


  • January 15th: On this date, you can start filing your individual tax returns. So if you want to avoid stressing out about the April 15 2021 due date, feel free to start filing your returns from mid-January. This date is also the deadline to pay your fourth quarter estimated tax payments.
  • January 31st: This is the last day to send out W-2 to employees and 1099 forms to contractors to whom you paid $600 or more during the past year. Also, it’s the last day to file FUTA form 940 for the previous year.


  • February doesn’t have any major tax deadlines, so you can breathe easy during this month.


  • March 15th: This is the annual tax due date for S-corporations, partnerships and non-single owner LLCs. This is also the last date to request an extension if needed which would give you an extra 6 months to file.

Key forms: 1065 and K-1. Be sure to find the correct one depending on your business structure (partnership, LLC, etc.) Sole proprietors will need a 1040.


  • April 15th: This year’s tax day is April 15th. 2020’s tax day date was extended to July 15th due to the pandemic. As of the time of writing this article, there have not been any extensions announced. This means that individuals, single-member LLCs and businesses that act as sole proprietors must file their taxes by this date. Also, if you won’t be able to file your taxes on this date, this is the last date to request a 6-month extension to file.
  • April 30th: This is the last day to file form 941 for the Employer’s Quarterly Federal Tax Return. This form is used to report your employees’ quarterly tax withholding tax amounts for estimated income, FICA, and FUTA withholdings.

Pro tip: Using a payroll provider often helps tremendously with this process.

Important note: FICA is a tax funding Social Security and Medicare. SECA is a similar tax for the self-employed (which is important depending on how you structure your business.) FUTA is the Federal Unemployment tax. Both FICA (or SECA) and FUTA must be withheld.


  • July 31st: This is the last day to file form 941 for the Employer’s Quarterly Federal Tax Return for the second quarter of the year.


  • September 15th: If your corporation was approved for an extension back in March, this is the last day to file your taxes.


  • October 15th: If you’re an individual or sole proprietor that was granted an extension back in April, this is the last day you have to file your taxes.
  • October 31st: This is the last day to file form 941 for the Employer’s Quarterly Federal Tax Return for the third quarter of the year.


  • After two action-packed months, you can take your mind off of taxes during November.

If You’re Going To File For An Extension

It’s important to file for an extension quickly. Don’t wait until the last day to request the extension. If you know you’ll need extra time to file your taxes, consider sending it at least 1 week before the deadline. Making the request online is easier. If you do it electronically, you’ll receive confirmation your extension was granted (typically in about 48 hours).

If you decide to send it via US mail, then you’ll have to contact the IRS directly to inquire about the status of your extension.

It is unusual for tax extensions to be rejected, but it does happen. The main reasons for denying are due to errors in filling the form or if out of date information is used. For example, if you use an old address that doesn’t match what’s on the IRS’s file, it might get rejected.

Estimated Tax Payment Dates

If you choose to do quarterly estimated tax payments because it works better for your type of income, here are the payment deadlines:

  • April 15th
  • June 15th
  • September 15th
  • January 15th

Keep in mind that if you are paying estimated taxes and the IRS determines that you underpaid when you filed your tax return, you might have to pay some penalties.

Making Payments On Time

If you are making your payments through the IRS Direct Pay portal, then you have until midnight of the due date to make the payment online. We don’t recommend waiting until the last possible minute, but it’s good to know just in case something out of your control happens.

If you make your payments through a third party, it’s always a good idea to make sure that you request a payment confirmation receipt from them.

The Best Tip For 2021 Tax Season

The best tip for this year’s tax season? File as early as possible and use direct deposit to make your payments. Since we’re still in the midst of a pandemic, this might mean that meetings with your accountant (in person) might be limited. At Bookkeeper360, our tax team is ready to remotely meet with you. Avoid the need to schedule appointments and worry about you and your team’s safety. We’re fully prepared for a virtual meeting to help you plan and file your taxes on time.

Note:If for any reason you need to go to an IRS office, you’ll most likely have to schedule an appointment and follow any guidelines that they have in place at the moment of the appointment.

During 2020’s tax season, due to the pandemic, the IRS decided to create an automatic extension for everyone from the usual April 15 date. As of the time of writing this article, there are no indications that this will happen again in 2021’s tax season, so if you have unanswered questions or changes to your accounting process, you should consider filing for an extension as early as possible.

In Conclusion

As you can see from this monthly breakdown, some months require more of your attention than others. This will depend on whether your business is a sole proprietor, LLC, corporation or any of the other business structures.

The main takeaway is that with proper tax planning you should be able to avoid last-minute form filling and stay clear of any extra fees or penalties due to not submitting the required forms in a timely manner. If you want additional peace of mind with your tax planning, tax strategy, or with your bookkeeping, then feel free to reach out.