My employer allows after-tax 401k contributions, and has an option for automatic quarterly after-tax 401k -> Roth 401k in-plan conversions. The other option for executing the mega backdoor Roth is to do an out-of-plan conversion, in which I can convert the after-tax 401k contribution to a Roth IRA, and the earnings on the after-tax 401k to a TradIRA.
Let's set up some numbers as an example. Let's say I contribute $10k after-tax, and my earnings before conversion are $1k.
Case 1: In the first case (in-plan conversion), I will have $11k in my Roth 401k, and I will have to pay income tax on the $1k.
Case 2: In the second case (out-of-plan conversion), I will have $10k in my Roth IRA, and $1k in my TradIRA. And I pay no income taxes.
Let's say at this point I've left my employer and the 401ks have been rolled over into IRAs. My primary question is about the consequences for withdrawal of principal (not earnings) in these two scenarios. Say I need $10k now.
Case 1: I have $11k in a Roth IRA. I can withdraw $10k from this whenever I want without tax consequences or penalty.
Case 2: I have $10k in my Roth IRA, and $1k in my TradIRA. I can withdraw $10k from my Roth IRA whenever I want without tax consequences or penalty.
Is all of this right so far?
If this is all right, I have a followup question about the ordering of withdrawals. Say I did in-plan conversions for 2 years with my employer, every year contributing $10k, and earning $1k before the conversion happens. Now I have $22k in my Roth 401k. Now I leave my employer and roll this over into a Roth IRA. Can I withdraw $20k from the Roth IRA without penalty? I'm concerned about the order of contributions and that I will have to pay some penalty on the portion of the withdrawal that comes from the $1k that was taxed.
(Assume for all of this discussion that I am under 59 years old and have had a Roth account for less than 5 years. Since this is all about withdrawing principal, this shouldn't really matter.)