The Illinois Department of Revenue (IDOR) is reminding taxpayers who missed April 15, 2025, income tax filing deadline that it is not too late to file and that prompt action can help minimize penalties and interest if a balance is owed. The original due date to file and pay Illinois individual income tax for calendar year filers is April 15, 2025. IDOR grants an automatic six-month extension of time to file a return and for those who file on a calendar-year basis, the new due date is October 15, 2025. If taxpayers receive a federal extension of more than six months, they are automatically allowed that extension for Illinois. An extension of time to file does not extend the amount of time to pay any taxes owed. If taxpayers determine taxes will be owed, they must use Form IL-505-I, Automatic Extension Payment for Individuals  to pay to avoid penalties and interest on taxes not paid by April 15, 2025. Additional information regarding payment options, penalties, or how to file, may be found by visiting tax.illinois.gov or calling 1-800-732-8866 or 217-782-3336.