another back door roth tax question

[Otodoc]

In Jan 2016 i contributed 5,500 to IRA for 2015 then converted in to roth few days later.  In Feb 2016 I contributed 5,500 to IRA for 2016, then converted it to roth few days later.  Do i fill out two 8606 forms?

[The White Coat Investor]

Yes. One for your 2015 taxes last year and one for your 2016 taxes this year. You did do one documenting the 2015 contribution last year, right? (If not, time for a 1040X).

[Otodoc]

No.  It appears that i did not.  i swore i read somewhere that you only had to report the conversions, not the contributions to the Trad IRA, since you aren't deducting it.  And the conversions were reported for year in which they were done, not the tax year it applied to.  So i was sure i was right.  I have since read the full explanation.  I was not right.  So i will be filling correction with the 8606 for 2015 now.  Thanks