Illinois Income Tax Extension

How to file an Illinois Tax Extension. Points to consider when to prepare extensions.

Extension Situation
Extension Suggestion
Illinois Tax Refund

Option 1: If you do not owe Illinois income taxes or expect a IL tax refund by the tax deadline, you do not have to prepare and file a IL tax extension. In case you expect a IL tax refund, you will need to file or e-File your IL tax return in order to receive your tax refund money.

Option 2: eFiled a Federal Extension? If you do not owe Illinois income taxes or expect a tax refund by the tax deadline, your accepted federal extension will be honored as a state extension, and you do not have to mail in Form IL-505-I.

Owe Illinois Taxes

Option 1: Pay all or some of your Illinois income taxes online via: MyTax Illinois.

Option 2: Illinois grants a 6-month extensions to IL taxpayers (which means you do not file an IL extension form) tax deadline in order to avoid late filing penalties. You can only eFile and IRS tax extension, but not an Illinois extension. The tax extension will only avoid late filing penalties until the October deadline.
Note: Keep in mind however, an Illinois or IRS tax extension does not extend the due date to pay the taxes you owe or income tax liabilities penalty free.

Option 3: Complete Form IL-505-I, include a Check or Money Order, and mail both to the address on Form IL-505-I. Important: Even if you filed an extension, you will still need to file your IL tax return either via eFile or by paper by the October deadline.

Illinois Income Tax Calculator
Illinois Tax Deadlines
Tax Penalties
Important: If you owe Illinois and/or IRS income taxes and do not file an IRS and Illinois tax return or extension by the Tax Due Date, you will be subject to IRS and IL late filing penalties. Estimate IRS late filing, payment penalties. In addition, if you do not pay your taxes by the Tax deadline, you will be subject to late tax payment penalties. Filing an extension on time will ONLY eliminate the late filing penalties but not the late tax payment penalties. Late filing penalties are generally higher than late payment penalties, thus file something on time even if you can't pay anything on time!
Taxpert®
Discuss your extension questions and goals with a Taxpert for free and we will guide you through the process.

WatchIT