Tax Deadlines Occurring in Calendar Year 2018 (for Tax Year 2017 Returns) Individual tax returns (Forms 1040, 1040NR, 1040A, and 1040EZ) First deadline is April 17, 2018 (File Form 4868 for extension). Extended deadline is October 15, 2018. Partnership returns (Form 1065) First deadline is March 15, 2018 (File Form 7004 for extension). Extended deadline is September 15, 2018. Trust and Estate income tax returns (Form 1041) First deadline is April 17, 2018. Extended deadline i