Hello,
I am planning to maximize my Solo 401K deductible contributions and I have a question regarding calculation for Solo 401K. It got more complicated after I entered the information in Turbotax!

1) I started a LLC in May 2012. I contributed $8K in my previous company’s 401K until then.
2) I started my Solo 401K and contributed the remaining 9K as “employee contribution” (before Dec 31,2012) – total of 17K for 401K contributions.
3) I received a profit of $132,390 as part of my company’s business (this number doesn’t include any self employment tax deduction). Per Turbotax, self employment taxes total were $5495. (I still have to enter more expenses and profit will lower but this is for an example).
4) If I click “maximize my contribution” button on Turbotax, it says I can contribute $34,481 more for “Self employed retirement”. How did that number get calculated? If I use the Fidelity calculator, it shows $33, 370.
5) I thought the calculation was 25% of (profit – (50%of self-employment taxes)). What am I missing? I didn’t think this calculation was this complicated?

Thanks in advance.