You may file Form 1040, Form 1040A or Form 1040EZ any time before the six-month extension period ends. You must make a proper estimate of your tax for the year.This extension will allow you to remit your business tax liability no later than 45 days from the delinquent date. This gives you until October 15 to file without penalties. We give you an automatic 6-month extension to file your return. Simply go to IRS.gov. Then, click on the "File an Extension" link. April 15, Calendar-year corporations - File a 2024 income tax return (Form 1120) or file for an automatic six-month extension (Form 7004). This must be requested prior to April 15. This is only an extension for filing paperwork, and taxes must be paid in advance of the deadline.