Does anyone know what the penalties are, if you cash out your 401K

If you are under 59-1/2 years of age, and assuming that you don't qualify for a hardship withdrawal under the terms of your plan, you will pay ordinary income tax on any withdrawals you make, plus a 10% penalty. Depending on your tax bracket and state income tax situation, you may end up with only about 50% of the value of your account.

You would be better off taking a loan from your 401(k) rather than taking a withdrawal.

ebaines is right on the money ( so to speak) you will pay tax according to your tax bracket ( both state and federal) and the 10 percent actual penalty itself.