8606 for prior years - Amend return or just file 8606?

[katrivedi02]

Situation

- I contributed $7,500 after tax to my IRA on 28-Dec-2023, but did not mention that in my 2023 tax return (i.e. did not include form 8606 for 2023).

- That amount grew to $7,925 by Feb and I converted that to Roth IRA on12-Feb-2024.

- I received 1099-R in 2024 from my brokerage company. Now I need to file 8606 for 2023.

- I know that the 2024 tax deadline has passed and I have filed extension for other reasons. I am trying to file 2024 taxes now.

Questions:

1. Can I just mail form 8606 to IRS, or I need to amend whole return (i.e. file 1040X)?

2. Will the delta amount $425 (=7925-7500) be taxable for year 2024?

[baldietax]

See this help page below which refers to process for filing prior year 8606, if it didn't affect prior year tax you just need to mail the form not amend your 2023 return.  When you do 2024 tax you'll need to provide the 2023 basis during the interviews, as it obviously wouldn't carry over.

the $425 will be taxable, form 8606 for 2024 will calculate the taxable portion of the conversion.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/retirement-benefits/enter-backdoor-roth-...