Illinois Extension
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Illinois grants an automatic six-month extension of time to file your return.
If you receive a federal extension of more than six months, you are automatically allowed that extension for Illinois.
Having an Illinois or federal extension doesn't grant you an extension of time to pay any tax you owe to Illinois. If you determine that you will owe tax to Illinois, you must use Form IL-505-I to pay any tax you owe to avoid penalty and interest on tax not paid by April 15, 2026.
Illinois grants an automatic six-month extension of time to file your return.
If you receive a federal extension of more than six months, you are automatically allowed that extension for Illinois.
Having an Illinois or federal extension doesn't grant you an extension of time to pay any tax you owe to Illinois. If you determine that you will owe tax to Illinois, you must use Form IL-505-I to pay any tax you owe to avoid penalty and interest on tax not paid by April 15, 2026.
