State tax filing

You don’t need to adjust your deductions on the nonresident California income tax return (Form 540NR) because of how California calculates tax for part-year residents.

California begins with your total income everywhere, then subtracts your standard or total itemized deductions (because it is using total income) to come up with California taxable income.

The base tax rate is based on the total income less total deductions number. California then prorates the actual tax based on your percentage of CA income. For example, if you earned 25% of your income in CA, your CA tax would be 25% of the base tax on all income.