I have no basis (nondeductible contributions) in my traditional IRA. I had made some nondeductible contributions back in the 1990s, then converted the account to a Roth when Roths became available (I believe it was 1999). So I have not filed an 8606 in over 20 years. I did make deductible contributions throughout the 2000s, and converted all but $1000 of those by the end of 2024. I converted that last $1000 in January of 2025. I then made a nondeductible contribution of $8000, and converted (plus 3 cents of interest) to a Roth. If we go by the last 8606, my basis was $0 (nondeductible contributions), and I converted all but $1000 in 2024. I did answer the question about contributing to an IRA between January 1 and April 15 2025. But I'm wondering, should my basis on the 2024 form 8606 be $0, or $8000? I will have to fill out the form for 2025 next year showing that I converted $9000.03, and I don't want to get taxed twice on that nondeductible $8000 (once being included in gross income in 2024, and once upon conversion).
