I just lost my job a week ago. I may be panicking too early, but I want to make sure I can provide to my family in the event it takes more than 6 months to find a new job. In the event I my cash available has evaporated what would be the impact if I take $100K out of my 401K plan in order to pay for my mortgage and other monthly expenses?

The minimum tax impact is the 10% Early Withdrawal Penalty, which cannot be mitigated by exemptions or deductions.

The regular income tax (state and federal) will range between 15% and 35%, depending on where you live.