Non-residents and part-year residents determine their California tax by multiplying California taxable income by an effective tax rate.

Effective Tax Rate - The effective tax rate is the California tax on all income as if taxpayers were California residents for the current tax year and for all prior tax years for any carryover items, deferred income, suspended losses or suspended deductions, divided by that income. (Cal. Rev. & Tax. Code Sec. 17041(b), FTB Publication 1100 – Revised 05/2020)

California Taxable Income (CTI) is California adjusted gross income (AGI) less California itemized or standard deductions.

California Deductions - Non-residents and part-year residents are allowed to claim itemized or standard deductions in computing their California taxable income in the ratio that California adjusted gross income is to total worldwide adjusted gross income (Cal. Rev. & Tax. Code Sec. 17304)

California Tax Credits - Part-Year and Non-residents may be able to qualify for California credits on a prorated basis if they meet all credit requirements.  They will be allowed all California tax credits in the same proportion as the ratio used to calculate their tax. (Cal. Rev. & Tax. Code Sec. 17041)

Exceptions - The percentage does not apply to the following credits, which are allowed in full for the: