What is personal income tax rate in california?

My friend told me it is about 18.5% for married. But I saw withholding tax is not more than 10% in most web pages. Can somebody explain me why? Are there other taxes? Thanks.

Public Comments

1. State tax rates range from 1% to 9.3% depending on income, with a 1% additional tax on income over a million dollars, so what your friend told you is overstated. See http://www.taxadmin.org/fta/rate/ind_inc.html This of course is in addition to federal tax.
2. If you look at Page 6 of the PDF linked below, you will see that the highest tax bracket for California individual income tax is 9.3%. It would not make sense to withhold more than that unless you are withholding extra to compensate for something (like self-employment income on the side that will generate extra taxes).