I'm filing taxes for my son who is a CA resident and worked at school in IL last year and then here in CA over summer.
As they appeared quite simple, I did it manually at first. Fed return matched fine, IL NR was easy too, and even figuring CA credit for other state taxes paid was fine manually. IL NR pro-rates the personal exemption, then charges a flat 4.95%, but CA taxes all the income.
When I paid to e-file via TurboTax, the CA state refund shows different calculations. It added both the IL state tax paid and CA state tax paid under the CA state taxes withheld.
Surely you can't take IL state taxes paid under CA taxes withheld AND get the other state credit? Or can you?
No, you may not.
Check the W-2 for the Illinois state tax paid. Does box 15 show California instead of Illinois? To view in TurboTax Online, follow these steps:
On the California state tax return, your son may be eligible for Other state tax credit code 187. You may claim this credit if you had income that was taxed by California and another state. The credit will offset the taxes paid to the other state, so you are not paying taxes twice.