The information given by ChelsiE2 above is correct. However, it does not address the question of what if you do some work in California and some in another state.
Let's take the simple case: you work for an employer as an employee or for a company as a contractor. For any day that you are physically working in California, then the income earned on this day is taxable in California.
For the employer who is working all year on a salary, this is relatively easier to figure - take the number of days spent working physically in California, divide by the total number of working days, and then multiply this ratio by the annual salary to get the amount of taxable income allocated to California.
Note that this does not affect your resident status for California tax purposes. If your domicile is in another state, then you file as a non-resident in California, even if you have California-sourced income. Please see the comments on part-year resident and non-resident at the Franchise Tax Board's website.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
