How do I report a number where the sum of Roth IRA contributions prior to 2018 is less than the sum of Roth IRA distributions prior to 2018?

[brbohall]

I have had a Roth IRA account since 1998.  The annual growth and Traditional IRA conversion have kept the Roth IRA in a positive balance even though distributions have been taken.  

Since a recommended document retention is for 7 years, I do not have all the information needed to make this entry which asks for contribution information back to 1998.

[dmertz · Accepted solution]

The answer is $0.  If you've already made distributions from your Roth IRAs of more than your original contributions to Roth IRAs, you basis in Roth IRA contributions has already been reduced to zero.  Once your basis in Roth IRA contributions was reduced to zero, your distributions begin to reduce your conversion basis, oldest conversions first.  If your total distributions prior to 2018 have exceeded the total of your Roth contributions and conversions prior to 2018, both your contribution basis and your conversion basis have already been reduced to zero.

If you were age 59½ or over, your Roth IRA distributions are qualified distributions, automatically tax and penalty free, so TurboTax does not need to know your basis since no Form 8606 needs to be prepared.  If you were under age 59½, the entire distribution is taxable if you have no basis remaining.