W-2 Box 12D — 401(k) Contributions
Total you contributed to your traditional 401(k) this year. Reduces Box 1 wages but not Social Security or Medicare wages.
Who pays it
Anyone contributing to a traditional (pre-tax) 401(k) plan.
How much
Whatever you contributed this year, up to the IRS limit ($23,000 in 2024).
Where it appears on your W-2
This IS a W-2 box — Box 12 with code letter D.
Tax impact
The amount here is excluded from Box 1 (federal taxable wages). It is still included in Box 3 (Social Security wages) and Box 5 (Medicare wages). That's why Box 1 < Box 3.
Common questions about BOX 12D
Is Box 12D the same as my paystub 401K total?
It should match your year-to-date 401(k) deduction on your final paystub. If not, contact payroll.
Why doesn't Box 12D include my employer match?
Box 12D is your contributions only. Employer match is not on your W-2 at all — it's an employer expense, not your taxable income.
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