In February 2024, I contributed $13,500 to a Traditional IRA in Vanguard using after-tax savings with the plan to attribute $6,500 to the 2023 tax year and $7,000 to the 2024 tax year. I immediately performed a conversion to my existing Roth IRA for a total of $13,505 due to the small amount of interest gained. I received a 1099-R in early 2025 that reflects $13,505 with the 2b boxes checked.
One mistake I realized this year is that I did not include the $6,500 TIRA contribution in my 2023 tax year return that I filed in April 2024. I amended that return recently to include this.
I put $7,000 on my 2024 tax year return for a Traditional IRA. I walk through the steps for the Roth IRA and follow the prompts to indicate that the $13,505 in the TIRA was converted entirely to a Roth IRA. When I do this, it adds taxes owed to my return.
If I include the $6,500 in my total basis as of December 31st, 2023, Turbo Tax will calculate no taxes due on the backdoor Roth conversion. Is this the correct approach even though I didn't contribute anything until early 2024? I did intend for the $6,500 to be classified as a 2023 contribution since it was prior to the April 2024 deadline.
To fix the 2023 tax year issue, do I fill out a Form 8606 and mail to my designated tax office? For 2024, do I need to fill out the same Form 8606 and include with my return submittal?
