What Does Box 12 Code BB Mean on a W-2?
Roth 403(b) contribution (after-tax). What it means, whether it is taxable, and what to do with it.
By the Easy Guides Editorial Team · Updated for 2026
Box 12 Code BB is roth 403(b) contribution (after-tax).
What Code BB means
Like a Roth 401(k), the benefit is tax-free qualified withdrawals later, not a deduction now.
Does Code BB affect my taxes?
Your Roth 403(b) contribution, the after-tax version of a 403(b). It's already included in your Box 1 wages, so there's no deduction.
Where to find Code BB on your W-2
Look at box 12, in the middle-right of the form. It has up to four lines, labelled 12a, 12b, 12c and 12d. Those letters are only line labels. The code you want is the small letter or pair of letters printed next to the amount, and it will read BB. If you have more than four entries, your employer issues a second W-2 to carry the rest.
Not the code you were looking for? The full box 12 code list covers every letter, and the W-2 box decoder explains every box on the form.