Hello all, I have a number of client's who did "back door" Roth contributions as their income was beyond the IRS threshold not allowing them to make such contributions in the prior year. Is 100% of this type of contribution "taxable" even though the taxpayer made the contribution with non-qualified money. I have read the fiduciary guidelines and I am still a bit confused on the taxability of this type of transaction. 

Can anyone give me some insight as how to determine how much if any of the back door Roth contribution is taxable. 

Thanks for your assistance.