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.We give you an automatic 6-month extension to file your return. This gives you until October 15 to file without penalties. Such filers should fill out the Form 4868 and send it to an address listed on the IRS website. The deadline for filing renewal statements may be extended up to 45 days, providing the time for filing the renewal statement has not already passed. The California tax deadline extension covers tax filing and payment deadlines initially falling between January 21, 2024, and June 17, 2024. However, filing and payment deadlines have been automatically extended to Oct. 16 if you have an address in a federally declared disaster area. The IRS has extended tax deadlines for most Californian taxpayers until November 16, 2023.