We grant an automatic six-month extension of time to file your return. This gives you until October 15 to file without penalties.Taxpayers do have the option of pursuing another extension on their income tax returns, but would have to do so prior to the Oct. A tax extension gives you an additional six months to file your taxes, with the extension deadline falling on Oct. 15. We automatically grant you a six-month extension of time to file your tax return. The state of Illinois grants an automatic sixmonth extension to file your Illinois individual income tax return (Form IL1040). If you need additional time to file your federal return, you can file for an Automatic Extension of Time to File Your U.S. Tax Return. How to file for an extension. You'll need to fill out Form 4868 and you can use the Free FIle tool to do so.