My situation: I am the sole employee of an S-Corp. In 2016, based on a reliable contract, I can expect a gross of $80K. Typically, I have $2-3K in expenses. I'm under 50. Because of our overall financial situation, my goal is to put as much as possible into the 401k. But the calculators I've found online are too simplistic.
I know I need to take into account payroll taxes (FICA, etc). And I don't know for sure but assume the $18K employee contribution means my wages are effectively reduced by that amount when calculating the 25% employer contribution. As near as I can come to an answer is this:
I gross 80K, need to account for 3K in expenses and also leave a 5K cushion in my business account, leaving 72K. I can subtract 18K as an employee contribution, leaving 54K. I also need to allow $12K for payroll taxes (16.75% of 72K). So 42K is left.
But here's where I have too little information. I obviously can't pay that 42K into my personal bank account because then there'd be no money left to actually make the employer contribution. So am I left paying myself 80% of 42K (33.6K) and only being able to employer contribute 8.4K?
I should also mention that of whatever amount ends up in my personal account, we don't care if a significant chunk has to go to income tax. The main goal here is to put as much as possible into the 401K.