topic Need to file form 8606 after return submitted (before tax filing deadline) in After you file

Need to file form 8606 after return submitted (before tax filing deadline)

cathiexu — Tue, 24 Feb 2026 06:54:13 GMT

Hi, I used Turbotax to generate my tax return for tax year 2022, and it's been mailed to IRS (not processed yet). However, I just realized it didn't include form 8606 (I had backdoor conversion to Roth), so I should have attached this form.

The tax filing deadline is Oct 2023 for extreme weather impacted California residents, and I'm eligible for extended deadline. Questions:

1. Do I need to file form 8606 only to IRS, or include all 1040 forms?

2. Should I pay for late filing penalty? Technically the filing deadline is Oct 2023 and now it is still before deadline, does my situation constitute late filing?

Thanks

Re: Need to file form 8606 after return submitted (before tax filing deadline)

fanfare — Mon, 24 Jul 2023 13:17:01 GMT

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

Do you have the correct taxable amount on Line 4b and did not take a deduction?

Get Form 1040-X from IRS website and mail it in with your 8606, which you can also get in fillable PDF.
Note: since you are not changing any dollar amounts on your amended tax return, you can leave all the lines 1-23 EMPTY.

Part III explanation: "didn't include Form 8606 with paper return".

Done this way, you sign 1040-X, not 8606

@cathiexu

Re: Need to file form 8606 after return submitted (before tax filing deadline)

cathiexu — Mon, 24 Jul 2023 15:55:30 GMT

@fanfare, thanks for your reply!

On my mailed 1040 for 2022, based on saved draft, it shows [4a] = $6k, [4b] = $0, so I don't think there is problem with my taxable income reflected on 1040 (And this implies that I did add Roth Conversion to software but not sure why 8606 wasn't generated eventually). In this case, should I only mail 8606 alone?

In addition, in either case, should I also mail the same thing to California state? Thanks!

Re: Need to file form 8606 after return submitted (before tax filing deadline)

fanfare — Mon, 24 Jul 2023 16:19:40 GMT

If you mail 8606 alone, IRS will send it back to you. (see recent forum post on this topic)

CA doesn't have Form 8606.

@cathiexu

Re: Need to file form 8606 after return submitted (before tax filing deadline)

cathiexu — Tue, 25 Jul 2023 07:04:50 GMT

Thanks @fanfare ! One last question, can I file 1040x+missing 8606 now (the original tax return is not processed yet)? Or is it better to file until original return is proceed?

many thanks!

Re: Need to file form 8606 after return submitted (before tax filing deadline)

fanfare — Tue, 25 Jul 2023 13:55:36 GMT

if you are getting a refund, you can wait for that refund.

If you are not getting a refund, you will not know when your 1040 has been processed by IRS.

returns without a refund get low priority.

@cathiexu

Re: Need to file form 8606 after return submitted (before tax filing deadline)

Critter-3 — Tue, 25 Jul 2023 14:20:13 GMT

The form 8606 is only needed if you had non deductible contributions to report ... a conversion from a 401K or IRA to a ROTH should not need one.