My conversion of a small part of my Traditional IRA (only pre-tax contributions from years past but zero in 2021) is fully taxable. The question of basis does not arise because none of my Traditional IRA accounts, including the one from which the conversion amount came, contains any after-tax contribution. I received a 2021 Form 5498 only for the Roth IRA account which received the rollover/conversion, but not from the other Traditional IRA accounts from where the rollover amount was withdrawn. I entered 1099-R for the rollover which shows the taxable amount (box 2a) is equal to the gross distribution (box 1), but the Taxable amount not determined (box 2b) is checked.
I subsequently said (i) Yes to the TurboTax query if all or part of the withdrawal was rolled over to Roth and (ii) No, I did not make and track nondeductible contributions to my IRA. The question of pro-rata basis calculation of (a presumed) back-door conversion and/or withdrawal from a Traditional IRA that is funded with after-tax money does not arise. Please advise how to tell TurboTax that the entire conversion amount is taxable and no calculation of basis is necessary
