The taxable amount not determined box is checked on my 1099-R from Charles Schwab. For instance say I had $10,000 in an IRA at the beginning of 2020 then contributed $6,000 of post-tax money to the IRA in May. Then in June converted the entire $16,000 (assuming no gains) to a Roth IRA at Charles Schwab. Shouldn't the taxable amount be $10,000 rather than the full $16,000? I am worried I am going to get taxed twice. Should I show the $16,000, from the 1099-R, as taxable then show a $6,000 non-deductible contribution for 2020? Or contact Schwab?
show what is on the 1099-R, but follow the questions in TT slowly and carefully, it should ask about what you did with the money (rolled it over) and ask about the cost basis so it gets to the $10,000 taxable amount in your example...just take it slow