<prompt> Human: Hey everyone I have a question about 401ks about what happened to me earlier this week. I work for a small engineering company that started a 401k program this summer so I signed up and started contributing. Soon I realized I was able to up my contributions to virtually all my paycheck to get as close as I can to the 17.5k limit. I had 90 of my paycheck goin in then on a whim I upped it to 99. I got a call from the girl who is our accounting department earlier this week saying that my contribution was too high and there wouldnt be enough of my paycheck left to have taxes and whatnot taken out so I had to revert to y 90 contribution. All of this is still very new to me but it doesnt sound quite right. I thought 401k money came out before tax so I should only be taxed on my remaining paycheck. Please let me know if I need to go into further detail.Thanks for the help!  <response>: Its income tax free but you still need to pay medicare and ssa tax. 