Feb 1st 2021 deadline to file to avoid underpayment penalties?

[robpet]

My understanding is that if you file by Feb. 1st you are not going to be charged underpayment penalties for taxes owed. If so, since this year filing only begins Feb. 12 was this Feb. 1st deadline also pushed out?

[ColeenD3]

You can mail it and have a postmark of February 1. 

Payment Due Dates You can pay all of your estimated tax by April 15, 2020, or in four equal amounts by the dates shown below.

1st payment . April 15, 2020

2nd payment  June 15, 2020

3rd payment  Sept. 15, 2020

4th payment  Jan. 15, 2021*

* You don’t have to make the payment due January 15, 2021, if you file your 2020 tax return by February 1, 2021, and pay the entire balance due with your return.

[robpet]

https://www.irs.gov/newsroom/2021-tax-filing-season-set-to-begin-february-12

The above was published 1/28 and has this list of dates

Important filing season dates

• Friday, February 12. IRS begins 2021 tax season. Individual tax returns start being accepted and processing begins.
• Thursday, April 15. Due date for filing 2020 tax returns or requesting extension of time to file.
• Thursday, April 15. Due date for paying 2020 tax owed to avoid owing interest and penalties.
• Friday, October 15. Due date to file for those requesting an extension on their 2020 tax returns.

The third line there only refers to late payment penalties and not underpayment penalties?

[DianeW777]

No.  The date the IRS begins to open and accept e-file returns does not relate to the underpayment penalties.

The February 1st deadline for the last estimated tax payment (regular due date January 15th) is not a new legislation.  Each year if you file your return by this date, then there is no underpayment penalty for the last quarterly payment.

The United States income tax system is a pay-as-you-go tax system, which means that you must pay income tax as you earn or receive your income during the year. If you didn't pay enough tax throughout the year, either through withholding or by making estimated tax payments, you may have to pay a penalty for underpayment of estimated tax. Generally, most taxpayers will avoid this penalty if they either owe less than $1,000 in tax after subtracting their withholding and refundable credits, or if they paid withholding and estimated tax of at least 90% of the tax for the current year or 100% of the tax shown on the return for the prior year, whichever is smaller. Click here for the IRS page updated 1/26/2021

[robpet]

Same rule applies for underpayment on W2s, right?

[DianeW777]

Yes, as far as it relates to the overall underpayment penalty.  The difference for W-2 withholding is that regardless of when the withholding takes place during the year, it is considered paid evenly throughout the year (no breakdown for actual withholding period required).