The contribution to a traditional IRA can be made between 1 Jan to 15 April of next year. It does not matter if you file an extension for your tax return, the deadline is still 15 April. Example: For the year 2023, the contribution to a traditional IRA can be done anytime between 1 Jan 2023 to 15 April 2024. To move this money from a traditional to a Roth IRA account, you can do it anytime. I suggest moving the money from traditional to Roth anytime before 31 Dec.