If you recharacterized the entire amount that was converted to Roth, you don't need Form 8606 to calculate the taxable amount of the Roth conversion since the Roth conversion is treated as not having happened. However, if you did only a partial recharacterization, Form 8606 will be needed to calculate the taxable amount of the portion that remained converted to Roth.
If your traditional IRA includes nondeductible contributions made for the current tax year, you must file Form 8606 whether you do any Roth conversion or not since the contribution adds to your basis and must be reported.
TurboTax takes care of all of this automatically when you enter the traditional IRA contribution, the Form 1099-R for the distribution converted to Roth, and your answers to the follow-up questions where you'll indicate the portion of the Roth conversion that you recharacterized back to a traditional IRA.
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.