Back door roth after filing taxes

[Nrm07]

I did a back door roth for both 2019 and 2020 in the year 2020, after I had already filed my 2019 taxes. Do I need to go back and amend my 2019 taxes to let the government know about my roth and file a 8606? Or just moving forward just make sure it’s right?

[GasFIRE]

If you did everything right, you should file the missing 8606(s) with a letter of explanation. Basis from the 2019 8606 needs to be entered on the 2020 8606. If you have any pre-tax tIRA that isn’t zeroed out by 12/31 such as a rollover IRA from a previous retirement plan or a SEPIRA, you could be subject to the pro-rata tax and would also need to amend your 2020 tax return.