Hello, I'm wondering if the IRS takes 21 days or 21 business days to process a filing? I'm trying to file for 2020 late before 12-31-21, to be eligible for the plus up..

[DoninGA]

Since you will have to print and mail the 2020 tax return, even during normal times it will take the IRS 4 weeks or longer to process a mailed tax return.  These are not normal times and it is taking the IRS up to 6 months and sometimes longer to process a mailed tax return.

[rjs]

The IRS is currently severely backlogged and is taking months to process tax returns. If you didn't get the full amount of the third stimulus payment that you are entitled to, you will be able to claim it as a Recovery Rebate Credit on your 2021 tax return.

[fanfare]

@supremegodofthei 

Your tax return filing date is the date the IRS receives it, not the date it is finally approved, which could take months.

It's not clear what you mean by "plus-up" and what you are expecting to happen.