Once you update the Recovery Rebate Credit questions under the "Federal Review" tab, your refund amount at the top of your page will update automatically.
Additionally, you will see a statement showing how much credit has been added on the page after you enter your stimulus payment information.
Here is a link to help you calculate what your credit amount should be.
The Recovery rebate credit is on 1040 line 30. It either adds to your refund or reduced a tax due.
Before filing, You can preview the 1040 or print the whole return
Let me explain how stupid the placement of the stimulus question in the interview flow is ... until you get to that point the program was including the entire stimulus credit you are eligible for based on your 2020 return but when you finally tell the program how much you already got in advance that same amount is removed from the estimated refund posted.
It would be nice if they would have asked for that information in the beginning in the MY INFO section BEFORE you entered in the income BUT the programmers did not ASK us posters in this forum AND they probably will not listen to us now and change the interview flow so I will be posting this answer A LOT this year.
LOOK at the form 1040 line 30 for the amount of the credit you are getting now on your tax return.