Since my Roth 401k is supposed to be deducted after taxes, I would expect that the amount I contribute would be included in the taxable wages on my W-2. However, when I compare my "Social Security Wages" (Box 3) to my "Wages, tips, other compensation" (Box 1), the difference is exactly the amount of my Roth 401k contribution listed in Box 12. The codes in box 12 are AA (Roth contributions to 401k plan) and D (Elective deferrals to 401k).
