How is turbotax calculating my 2020 amendment?

[giorgi3]

I missed a W2 of my wife's for $4500 when I originally filed my taxes. When I use turbotax online to file the amendment the net change to line 1 is $8400. Where did turbotax come up with the extra $3900?  

Any help would be greatly appreciated!

Thanks

[SweetieJean · Accepted solution]

Did either of you also receive Social Security benefits?   If so, more of that may have become taxable as a result of  the additional W-2 income.

[giorgi3 · Accepted solution]

That's it!

For some reason I thought we were at the max for taxable SS but that wasn't the case.  I found this IRS link to manually calculate my taxable SS:

https://www.irs.gov/help/ita/are-my-social-security-or-railroad-retirement-tier-i-benefits-taxable

Sure enough, adding a w2 for $4500 increased my taxable SS by $3900. 

Thanks so much SweetieJean!!  Your a life-saver!