My company matches my 401k contributions, up to a limit, 6%. I don't currently contribute the max, but I would like to start. I know when I increase the W4 allowances, my take-home pay goes up, and the opposite is true when I increase the amount contributed to my 401k. I want to net take-home pay to remain the same. Is it a good idea to increase the number of W4 allowance I am claiming in order to contribute more to my 401k? How will this affect the amount of taxes I owe at the end of the year?
Edited for clarity: All else being equal, say I have my W4 allowances perfect to where I owe $0 and receive no refund at year end. If I add an allowance to my W4, I'll take home say $300 more per paycheck. If I contribute an additional $390 to my 401k (this is adjusting for the fact 401k contributions are pre-tax, keeping net takehome pay the same), will I owe more come year end?