Do I need to file Form 8606?

[Socket1021]

 Since I am retired, I no longer contribute to my IRAs, and I am also below RMD age.  On the advice of my financial advisor, I did a partial conversion to a Roth IRA from my traditional IRA in both 2024 and 2025, and I made estimated tax payments to cover the income tax due on the IRA conversion to avoid underpayments.  

Because I had never done a conversion before, I had an outside accountant do my taxes for me.  He did not include  a Form 8606 in the filing.  When I did my taxes this year on TurboTax, I was not prompted to fill out Part II of Form 8606, either.  In both years, the full amount of the conversion was included in my income and reported on my 1040. 

Do I still need to manually file Form 8606 for both 2024 and 2025? It seems redundant because I am being taxed on the full amount of the conversion.  Thank you.

[MaryK4 · Accepted solution]

Yes, if you converted from a traditional IRA to a Roth IRA, you must include a Form 8606 for each year you converted. Yes, you are correct that it is already taxed based on the 1099-R entry; but if there were any nondeductible traditional IRA contributions, the pro-rata taxable amount would be recorded on the 8606.  

[Socket1021]

Thank you.  I went back into Turbotax and was able to get the Form 8606 to generate.

For 2024, I believe that I have to file Form 1040-X, leave lines 1-23 blank, since my tax liability has not changed, and attach Form 8086 for 2024, noting that it was omitted from my 2024 return.  Is that correct?  Thanks again.

[MaryK4]

@Socket1021 No, you can actually mail the 8606 separately without amending the tax return.  Here is the link to the IRS Form and Instructions- About Form 8606, Nondeductible IRAs.  

[Socket1021]

So I just mail the 2024 Form 8086 without explaining why I am sending it in?  That sounds like a recipe for confusion. With Form 1040-X, there is a place for why I am sending in a form, at least.

[MindyB]

Yes, it will be apparent that a 2024 8606 that is signed by you and mailed to the IRS is a form that you'd like added to your record.  

If you'd prefer, you certainly can add a letter.  You could include a brief cover letter with your mailing to help the IRS process your form. Your letter should clearly state your full name, current address, and Social Security number at the top. Explain that you are sending a standalone Form 8606 for the 2024 tax year to report IRA contributions that were left off your original return. 

Since you are writing the letter, you could also request they waive the $50 late penalty. To avoid the penalty, you should explain in your own words that you didn’t realize a separate form was necessary because your tax total stayed the same, but you are proactively fixing the error now to ensure your future retirement records are correct. It is important to specifically use the phrase "reasonable cause" in your explanation to let the IRS know you made an honest mistake in good faith and are requesting they waive the $50 fee.

[fanfare]

The proper way to file Form 8606 is attached to Form 1040-X.
Form 8606 can be signed and mailed by itself only when you are otherwise not required to file a tax return.

@Socket1021