How do I determine my filing status for individual income tax?

In general, you should use the same filing status as on your federal return; however:

  • If you file a joint federal return and you are an injured spouse (e.g., your spouse owes a liability, for which you are not responsible, to a government agency), you should file separate Illinois returns using the "married filing separately" filing status. Do not recalculate any items on your federal return. Instead, you must divide each item of income and deduction shown on your joint federal return between your separate Illinois returns following the Allocation Worksheet in the Form IL-1040 Instructions.

    You may choose to file separately as an injured spouse only until the extended due date of the return. Once you choose a filing status, the decision is irrevocable for the tax year.

    Note: If you choose to file a joint Illinois return, we may take the entire refund to pay your spouse's liability.

  • If you file a joint federal return and one spouse is a full-year Illinois resident while the other is a part-year resident or a nonresident (e.g., military personnel), you may choose to file "married filing separately." Do not recalculate any items on your federal return. Instead, you must divide each item of income and deduction shown on your joint federal return between your separate Illinois returns following the Allocation Worksheet in the Form IL-1040 Instructions.

    If you choose to file a joint Illinois return, you must treat both your spouse and yourself as residents. This election is irrevocable for the tax year. You may be allowed a credit for income tax paid to another state on Schedule CR. For more information, see the Schedule CR instructions.

    If you originally filed a joint return, but did not treat both yourself and your spouse as Illinois residents, you must correct that error either:

    • by jointly filing Form IL-1040-X, Amended Individual Income Tax Return, treating yourselves as Illinois residents or

    • by filing seperate IL-1040-X forms, even if the extended due date has passed. If you file separate IL-1040-X forms, do not recalculate any items on your federal return. Instead, you must divide each item of income and deduction shown on your joint federal return between your separate Illinois returns following the Allocation Worksheet in the Form IL-1040 Instructions. Any spouse filing as a nonresident or part-year resident must also attach a completed Schedule NR, Nonresident and Part-Year Resident Computation of Illinois Tax.

  • If you are in a civil union, you must file your Illinois return using the same filing status as on your federal return.

If you have additional inquiries, you may submit them to the Questions, Comments, or Request form.