My spouse receives Social Security and I am self-employed, and we both took IRA distributions for 2021. I plan to contribute to my IRA for 2021 based on my self-employment income (at the prompting of TurboTax). When I add in my IRA contribution, TT now calculates the taxable portion of the Social Security income using the "Social Security Recipients Who Contribute to a Traditional IRA Worksheet". However, I can't figure out where it is getting the number for the Modified AGI used in line 1 of Worksheet 1, "Computation of Modified AGI". It looks like it should be from IRS Pub 590-A (Appendix B & C) but if I follow the instructions in Appendix C of that publication, I get a much higher number.
When I go to Forms and ask for the data source, I get the following popup:
"Generally, the amount on line 1 will be the amount shown on line 38 of Form 1040 not including any social security benefits, the series EE bond interest exclusion from Form 8815, excluded adoption benefits from Form 8839, the deduction for student loan interest, the domestic production activities deduction, or any traditional IRA deduction. However, if the taxpayer or the spouse also received a distribution from a traditional IRA, a special calculation is made to determine the amount on this line and may not agree with the amount on line 38 of Form 1040."
The reference to line 38 of Form 1040 seems to be for a previous year. But I am wondering what is this "special calculation"? Is there a way to check the numbers?
