I took an early withdrawl from my 401k and I want to estimate the taxes that I will owe. I know there is the standard 20%. A 10% penalty and 10% for taxes. Am I correct and saying that I have to add that withdrawl as income and then check to see what tax bracket I will fall in. For example annual income is ~ 100K + 50K withdrawl = ~ 150K income which falls in to the 28% income tax bracket. So to figure out how much money I need to pay in taxes on the withdrawl money (50K) I multiplied the 50K by 28% and got ~
14K. Is that an accurate guess ?

Yep, that's pretty accurate.

Now add 10% tax on the $50,000 ($5,000) as the penalty tax on early withdrawal.

This type of withdrawal should be avoided at all costs. Borrow the money elsewhere if possible.

Let us NOT forget the state income tax liability, which can be as high as 9.55% in California.