State Income Taxes

Disclaimer: No information on this page was prepared by a certified public accountant, and it should in no way be considered as tax advice. This is by no means a comprehensive tax resource and the people contributing to it are, just like you, students and researchers. It's meant as a guide on filing income taxes, but you should base your final decisions on information from either the IRS or the FTB.

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If you receive a salary while residing in California, you're generally required to file income tax returns by the April 15th deadline every year whether you're a US Citizen or not.

To complete your California State Income Tax Return, you'll generally need your Federal Income Tax Return complete beforehand, and since most of the procedure is the same, you should read the previous document first.

The Franchise Tax Board (FTB) website is the place where you should find the answer for every kind of question regarding your California state taxes. You might also want to contact the ASUC Student Legal Clinic for more personalized tax help.

Filing Methods

You can choose whether to file your taxes by completing the forms and then either mailing them to the FTB or taking them with you to the nearest FTB office (useful if you have tax questions and prefer to double check before filing) or you can use the free CalFile.

The rest of this document will concern preparing, filing and paying your tax return manually and can still serve as an information resource for people who e-file for convenience.

Preparing your Tax Return

For an extensive list of downloadable forms, please refer to this FTB webpage.

The most common tax form for US Citizens is the 540, which you can download from the above website alongside its instructions. If you qualify, as probably most of us do, you should check out the 540A or, even better, the 540 2EZ, which are simplified versions of the previous form. To check if you qualify, you should read their particular instructions.

I'd assume Non-Residents should fill out the equivalent forms with the NR subscript (e.g. 540NR).

Whatever your required choice of form, refer to their instructions for answering any doubts about them. Be sure to check the taxable income page as well.

Paying and Filing your Tax Return

To pay your state taxes, you can either mail a check or money order with your tax return or pay electronically by electronic funds withdrawal (if you e-file or CalFile), by credit card (by phone or online, but it generally requires a fee), or by the free Web Pay. You can use either the last one or the electronic funds withdrawal from CalFile for free. Note that for making a web payment as well as for using CalFile you need your Customer Service Number (CSN), which you can get online or through the phone during normal businees hours (the last method is required if this is the first time filing).

If you were to mail your tax return, you should address it to:

Franchise Tax Board
PO BOX 942867
Sacramento, CA 94267-0001

And if you were to take it to the nearest office, that is:

1515 Clay Street, Suite 305
Oakland, CA 94612-1431

Estimated State Taxes

Most people aren't required to pay estimated taxes quarterly unless one of their employers, or a fellowship they have, doesn't withhold taxes for them. If this were the case, US Citizens should refer to form 540-ES (Non-Residents might use this same form) to check if they indeed are required to pay quarterly payments during the upcoming year.

As a general rule, you must make estimated tax payments if you expect to owe at least $100 in tax for the upcoming year and your withholdings and credits will be less than the smaller of:

  • 90% of the tax shown on your upcoming tax return,
  • Your previous year tax.

Exception: You won't be required to make estimated tax payments if you're a nonresident or new resident this last year and did not have to pay any taxes this last year.

It might be useful, though, to pay taxes quarterly rather than being faced by the full amount at the end of the year. In any case, completing form 540-ES will inform you of your approximate upcoming year taxes so as to prepare accordingly.

The schedule for estimated tax payments is the following:

  • 1st: ~April 15
  • 2nd: ~June 15
  • 3rd: ~Sept 15
  • 4th: ~Jan 15

Note: Dates will move forward if they fall on a weekend.

As long as you at least pay your required amounts by the above deadlines then you won't be penalized. If you underpay one of your estimated payments, though, the remaining amount will incur a penalty which will depend on the number of days it stays unpayed.

Payment methods are the same as those outlined in the previous section. Once again, Web Pay is the recommended method as it lets you schedule all your payments as far as a year in advance.

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