W-2 - Information about Box 12
The following list explains the codes shown in box 12 on the W-2.
Box 12 Code
Uncollected Social Security or RRTA tax on tips
Uncollected Medicare tax on tips
Taxable cost of group-term life insurance over $50,000
Elective deferrals to a section 401(k) cash or deferred arrangement. Also includes deferrals under a SIMPLE retirement account that is part of a section 401(k) arrangement
Elective deferrals under section 403(b) salary reduction agreement with your employer
Elective deferrals under a section 408(k)(6) salary reduction SEP
Elective deferrals and employer contributions (including non-elective deferrals) to a section 457(b) deferred compensation plan
Elective deferrals to a section 501c(18)(D) tax-exempt organization plan
Nontaxable sick pay (information only, not included in boxes 1, 3, or 5)
Twenty percent (20%) excise tax on excess golden parachute payments
Substantiated employee business expense reimbursements (nontaxable)
Uncollected social security or RRTA tax on taxable cost of group-term life insurance over $50,000 (former employees only)
Uncollected Medicare tax on taxable cost of group-term life insurance over $50,000 (former employees only)
Excludable moving expense reimbursements paid directly to employee (not included in boxes 1, 3, or 5)
Nontaxable combat pay
Employer contributions to your Archer MSA.
Employee salary reduction contributions under a section 408(p) SIMPLE plan (not included in box 1)
Adoption benefits (not included in box 1)
Income from exercise of non-statutory stock option(s) (included in boxes 1, 3 (up to social security wage base), and 5)
Employer contributions (including amounts the employee elected to contribute using a section 125 (cafeteria) plan) to your health savings account
Deferrals under a section 409A nonqualified deferred compensation plan
Income under section 409A on a nonqualified deferred compensation plan. This amount is also included in box 1. It is subject to an additional 20% tax plus interest.
Designated Roth contributions under section 401(k) plan
Designated Roth contributions under section 403(b) plan
Cost of employer-sponsored health coverage (this is not taxable when Code DD)
Designated Roth contributions under a governmental section 457(b) plan. This amount does not apply to contributions under a tax-exempt organization section 457(b) plan.