Retirement tax questions

A back door Roth IRA conversion is a special kind of IRA rollover. There is no dollar limit to a rollover, rollovers are not contributions and are not governed by the same rules. You may rollover the entire IRA balance to a Roth IRA if you choose.

If your current balance is $16,000 and your nondeductible basis is $15,000, only the $1000 difference will be taxable.