US Tax Tools

W-2 Box 12 Code AA — Roth 401(k) contributions

Your designated Roth 401(k) contributions. Already included in Box 1 (taxed now), but qualified distributions in retirement are tax-free.

At a glance — Box 12 Code AA

Box name
Roth 401(k) contributions
Reports to
Already in Box 1. Feeds Form 8880 (Saver's Credit).
Check against
Your 401(k) statement's Roth contribution YTD total.

What Box 12 Code AA means

Code AA reports designated Roth 401(k) contributions — after-tax dollars that grow tax-free and can be withdrawn tax-free in retirement if the Roth account has been open 5+ years and you are 59½+. Unlike traditional 401(k) code D contributions, code AA does NOT reduce Box 1 — you are paying income tax on this money now.

The combined §402(g) limit applies to traditional (code D) + Roth (code AA) — you cannot exceed the annual cap total across both. For example, you can split the year's limit between the two however you like, but the sum cannot exceed the cap.

Tax return implications

  • No effect on Box 1 (already included).
  • Counts toward Saver's Credit up to the credit limits.
  • SECURE 2.0 §603 (live as of plan year 2026) requires catch-up contributions to be made as Roth (code AA) for participants whose prior-year FICA wages from the plan-sponsoring employer exceeded the §603 high-earner threshold (statutory base $145,000, indexed for plan years after 2024) — cannot be code D.

Common pitfalls & things to check

  • Don't mix up code AA with code D — AA is Roth (after-tax, tax-free growth), D is traditional (pre-tax, taxed at distribution).
  • Roth 401(k) employer matching historically goes to the pre-tax side — ask HR if you want the match as Roth (SECURE 2.0 allows it).
  • The 5-year Roth 401(k) clock is plan-specific; rolling to a Roth IRA may start a new 5-year clock on the IRA side.

For 2025 returns (filed by April 15, 2026)

§402(g) elective deferral limit
$23,500
Age-50 catch-up $7,500 · SECURE 2.0 ages-60–63 super-catch-up $11,250 · §415(c) total additions $70,000. Combined across code D + AA (traditional + Roth).

Values sourced from central tax-year config at build time — update automatically on FY rollover.

Related W-2 boxes

Reconciling your W-2 at tax time? Use the paycheck calculator to verify expected federal, Social Security, and Medicare withholdings on your salary, and the federal income tax calculator to estimate your refund or balance owing before you file.

Sources

W-2 box definitions per IRS General Instructions for Forms W-2 and W-3 and IRC §6051. Rates and thresholds current for tax year 2025 (file by April 15, 2026); 2026 figures included where published.

Last updated May 14, 2026 Tax year 2025-26

Data sources: IRS (irs.gov), Social Security Administration

This tool is general information only, not financial advice.

Reviewed by USTax Tools Editorial Desk

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