I received form W2 with pension contribution on line 12, code D; also have a business in which I am the only employee and for which I have opened a solo 401(k). I purchased TurboTax 2025 Home and Bu...
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I received form W2 with pension contribution on line 12, code D; also have a business in which I am the only employee and for which I have opened a solo 401(k). I purchased TurboTax 2025 Home and Business and would like to maximize my tax deduction for my contributions to my solo 401(k). After trying to understand this via reading online, I deducted the amount on form W2 line 12 code D from $23,500 (the IRS 2025 maximum employee contribution); I entered that on line 6(a) of the 2025 Keough, Simple and SEP worksheet. I did not click on lines 1(d), 2(d) or 4(d) of the worksheet (by which to calculate the maximum deductible contribution for multiple plans, profit sharing plan, SEP). However, line 6(f) also has a "calculate the maximum deductible contribution" box. If it is checked, the total tax liability is lower than if it is not; the the calculations on the rest of the worksheet are exactly the same, except that, if the box in line 6(f) is not checked, the amount that is transferred to Schedule 1, line 16 as an adjustment to income is less. Here are my questions: (1) Is the procedure I used correct? (2) What is the reason for the difference when the box in line 6(f) is checked versus when it is not? (3) Why does TurboTax apparently not automatically deduct pension contributions in W2 line 12 Code D that have been inputted into TurboTax and why does it seem TurboTax does not support automatic calculation of the maximum deductible solo 401(k) contribution when the W2 also contains a contribution? The W2/solo 401(k) contribution issue comes up repeatedly in TurboTax fora and it seems it should be possible to support. (4) Finally, it would be very helpful if my TurboTax program provided a clear explanation of which amount should be deposited into the 401(k) as the employer contribution and which amount as the employee contribution, and when to check the various maximization boxes; these are difficult to figure out oneself. Is there anywhere this is shown in my Home and Business program, and, if not, could such an explanation be given here?