W-2 box 12 code BB.

What code BB means

IRS description: Code BB: Designated Roth contributions under a section 403(b) plan. Use this code to report designated Roth contributions under a section 403(b) plan. Do not use this code to report elective deferrals under code E.

If you work for a school, hospital or nonprofit with a 403(b), code BB is how a Roth election shows up. The employer-facing rule in the instructions is blunt: code BB is only for the designated Roth money, and pre-tax elective deferrals under a 403(b) belong in code E. Because the money was taxed when you earned it, the IRS requires it to be reported in boxes 1, 3 and 5, so there is no box 1 reduction to notice.

BB is reported separately from E, so the W-2 shows which dollars were Roth. Keep your plan statements, since a W-2 shows only one year.

Where code BB shows up on your W-2 and return

• Box 1: included. You paid income tax on the contribution when you earned it.
• Boxes 3 and 5: included.
• Box 13: a 403(b) annuity contract or custodial account is on the IRS list for the Retirement plan box.
• Form 1040: no extra entry. The 2025 Form 1040 instructions say an excess Roth deferral is not added to line 1h because it is already in box 1.

Worked example

A hospital employee earns $55,000 and splits her 403(b) as $3,000 pre-tax and $2,000 Roth. Box 12 shows E 3000.00 and BB 2000.00. Box 1 is $55,000 − $3,000 = $52,000, because only code E comes out. Her 403(b) total for the year is $5,000 out of a $24,500 limit, leaving $19,500. If she also deferred at a second job, the two W-2s are added together for the limit.

Limits and what to check

The 403(b) limit for 2026 is $24,500, with catch-up of $8,000 at age 50 and over and $11,250 at ages 60 to 63 (IRS news release, read November 1, 2026). Designated Roth and pre-tax deferrals share that limit across all your employers. People who qualify for the 15-year rule in Publication 571 may be allowed a higher 403(b) limit, as the 2025 Form 1040 instructions note, so ask your plan administrator. If total deferrals go over, the plan can return the excess and its earnings and report the return on Form 1099-R.

Common mistakes

• Assuming BB reduces box 1. It does not; code E does.
• Treating BB as a separate allowance. It shares the same limit as code E.
• Reading a missing E as an error. A pure Roth election produces BB with no E at all.
• Forgetting Roth 403(b) money is taxed now. Any later qualified withdrawal rules come from the plan, not the W-2.

See every code in one searchable table on the W-2 box 12 codes lookup.

Sources

Primary sources opened on November 1, 2026. The plain-English parts of this page are our summary of them, not IRS guidance.

• IRS, General Instructions for Forms W-2 and W-3 (2026), Box 12, Codes (read 2026-11-01): code BB definition, the "do not use for code E" rule and the Roth reporting rule
• IRS news release: 401(k) limit increases to $24,500 for 2026 (read 2026-11-01): 2026 limits and catch-up amounts
• IRS, Instructions for Form 1040 (2025 edition, latest read): excess elective deferrals (read 2026-11-01): excess designated Roth contributions and the 15-year rule note