Retirement tax questions

Same circumstances as others except I have $$ left in my traditional IRA. I have a traditional IRA to which I have been contributing since 2012, all non deductible.  Since 2018 I started taking chunks to convert to Roth.  How can I tell if my taxable amount is correct on turbotax? Last years conversion (1st one) resulted in no tax and this year it’s quite significant, increasing my taxes by almost $1k.  I did the contribution section as well but I need to verify TurboTax is properly calculating the taxable amount.  How can I see that? I also missed a contribution which I did in 2019 for 2018 so that would increase my basis.  Help please