Boxes 15-20 of your W-2 is for state info. Box 17 is the withheld state tax. Ohio also has city income tax. If you worked in a city with a tax, that info will be in boxes 18-20. You do not have to file an OH city tax return, but they get to keep the amount in box 19. CA will not give you a credit for city tax paid.
State tax general rule. State tax rule. The general rule is: your report all your income on your home state return, even the income earned out of state. You file a non-resident state return for the state you worked in and pay tax to that state. Your home state will give you a credit, or partial credit, for what you paid the non-resident state. You will have to file a non resident OH state return and pay OH tax on the income earned there.. You will also file a CA full year resident return and calculate tax on ALL your income. CA will give you a credit, or partial credit, for the tax you pay OH. So, there will be little or no double taxation, but you have the cost and hassle of filing two state returns. Do the nonresident state return first.
