Arizona Filing Due Date: Corporation income tax returns are due by the 15th day of the 4th month following the end of the taxable year — or April 15 for calendar year filers.
Extended Deadline with Arizona Tax Extension: An Arizona extension will give you 6 extra months to file, which moves the filing deadline to October 15 (for calendar year taxpayers). Note that Arizona partnerships are given a 5-month tax extension.
Arizona Tax Extension Form: To request an extension, use Arizona Form 120EXT (Application for Automatic Extension of Time to File Corporation, Partnership, and Exempt Organization Returns). To avoid late filing penalties from the State of Arizona, your filing of Form 120EXT must be postmarked by the original due date of your return.
Arizona Extension Payment Requirement: An extension of time to file is not an extension of time to pay. You must pay at least 90% of your state tax liability by the original deadline to avoid the extension underpayment penalty. You can make an extension payment with Form 120EXT, or online through Arizona’s E-Services for Businesses: www.azdor.gov/EServices/Business
Arizona Tax Extension Tip: If you have filed a valid Federal business tax extension, you will automatically receive an Arizona extension for the same period of time. In this case, there is no need to file Form 120EXT unless you are making an Arizona business tax extension payment.