Self employed 401k & W-2 employee 401k

[Mjsfurkids]

I am self-employed as well as have a W-2 position with another unrelated employer. When using Turbo tax to calculate the maximum I can contribute to my solo 401K, it doesn't appear to be factoring in the 401k deferral made with my W-2 employer, as entered on the W-2 details.  I contributed the maximum ($22,500 + $7,500 catchup) as a W-2 employee, however, when I select "Maximize Contribution to Individual 401k" TurboTax indicates I can defer $30,000 (elective deferrals/catchup) and then the total amount it indicates needing to be contributed by the tax filing deadline appears to contain the additional amount in employer matching (profit sharing) contributions.  Thus, it appears to be making the amount to contribute by the tax filing deadline (and affecting the amount of income tax owed) incorrect by $30,000.  I believe I can only do the employer profit sharing portion (e.g., net profit less deductible portion of SE tax)  which would mean subtracting $30k from the amount Turbo Tax is indicating I need to contribute by the tax filing deadline. However,  I would think this is then inaccurately reporting my tax liability on my income tax return.  Any direction is appreciated! 

[dmertz]

You are correct, TurboTax is unable to take into account deferrals you made to other employer's plans, so you can't use the Maximize function for an individual 401(k).  Since you've already done the maximum elective deferral, you can cause TurboTax to calculate just the permissible employer contribution to the self-employed 401(k) and put only this on Schedule 1 by using the Maximize function for a SEP contribution instead.