To enter this into TurboTax, you must split the Form 1099-R into two, one for the portion rolled over to the Roth IRA and the other for the portion rolled over to the traditional IRA as follows:
For the portion rolled over to the traditional IRA:
Assuming that the code in box 7 is G, in the follow-up indicate that you did not roll this portion of the distribution over to any kind of Roth account.
For the portion rolled over to the Roth IRA:
In the follow-up, indicate that you rolled this distribution over to a Roth IRA.
Note that the dollar amounts in the boxes of the two Forms 1099-R that you enter will total to the same amount as on the original Form 1099-R.
To enter this into TurboTax, you must split the Form 1099-R into two, one for the portion rolled over to the Roth IRA and the other for the portion rolled over to the traditional IRA as follows:
For the portion rolled over to the traditional IRA:
Assuming that the code in box 7 is G, in the follow-up indicate that you did not roll this portion of the distribution over to any kind of Roth account.
For the portion rolled over to the Roth IRA:
In the follow-up, indicate that you rolled this distribution over to a Roth IRA.
Note that the dollar amounts in the boxes of the two Forms 1099-R that you enter will total to the same amount as on the original Form 1099-R.
Wouldn't it make sense to change the code from G to H for the after tax split of the 1099R? If not, this amount would be considered taxable at some point.
No. A code "H" says the money came from a 401(k) Roth (Designated Roth), not a 401(k). This particular transaction is not taxable because the before-tax money is rolled to a before-tax Traditional IRA and the box 5 after-tax money is rolled to an after-tax Roth IRA. Neither one is taxable with a zero in box 2a.
What about clarifying the meaning of the follow-on q about making any after-tax contribution to the 401k, if done by payroll deduction? Unless I hear otherwise, I’ll presume the q. means a direct contribution by myself other than via payroll.
Some 401(k) plans allow additional after-tax contribution after the before-tax limit has been reached. That would normally be reported by the employer in box 5 on the 10990R or on quarterly or yearly account statements that report the 401(k) balance before and after tax amounts.
Understand. That's exactly what happened, but how, then is the follow-on question to be answered? Does it matter?
Which follow-up question but please don't answer here.
It would be best if you started a new thread with your own question and provide the details (box 7, box 2a, box 5, etc) rather than confuse this thread (that is about splitting a rollover) with off-topic questions.