Do I need to show an after-tax 401k (not Roth) contribution on my taxes (my firm allows us to contribute up to $10K to an after-tax 401k beyond the $18K Roth 401k limit)?

[null309]

I'm asking specifically if I need to denote anywhere that I contributed an additional amount to an after-tax 401k account, not about the contribution I made to my Roth 401k.  Thanks!

[dmertz · Accepted solution]

The only place you would enter it into TurboTax would be for the Retirement Savings Contributions Credit, if you qualify for the credit, when TurboTax asks you to enter your after-tax contributions.  Most people making after-tax contributions to a 401(k) have income high enough to disqualify them from receiving this credit, so it's unlikely that you would need to make this entry.