IRS calculates taxable Social Security benefits differently from TurboTax

[SteamTrain]

@TurtleToo 

One thing you might try, other than getting the Desktop program as @rjs suggested?

If you already have a copy of your Full TTX  tax return, with all the worksheets as a PDF file, then you could print out just the TTX  SS worksheet in that PDF.  That worksheet contains all your current values, and you would manually add-in the income you apparently missed (lines 1-thru-4 or other lines) then go thru the calculations in any of the lines that follow to see what changes to see if the final result on line 20 approaches what the IRS thinks it should be.

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If you do not have the TTX SS worksheet, you'd have to get back into your tax return using the "Add a State" selection (you won't have to actually add one)...then go to the Print Center and download a NEW copy of your tax file as a PDF...BUT, you need to make the selection to include all the worksheets so that the TTX SS worksheet is included.  Then get out of there....DO NOT actually change anything in your tax file.  You don't want to mess anything up until such time as you decide you truly want to start an "amended" tax return.  (If you do end up doing that, you have to start the actual amendment process before you make any changes)

[TurtleToo]

You're a genius.  Luckily I did my 2022 taxes with the PC version.  I launched the app and added the income that the IRS found.  I recalculated the tax owed and printed out the PDF of the new return and worksheets.  The taxable portion of SS now matches what the IRS calculated.  Also, the IRS does not require me to file a 1040X.  I just have to pay the additional tax owed within 30 days.  Thanks so much for your advice and help.