I have an amount in box 12 on my W-2. What is this?

The following list explains the codes shown in box 12. You need this information to complete your tax return. 

A- Uncollected Social Security or RRTA tax on tips

B-  Uncollected Medicare tax on tips

C-  Taxable cost of group-term life insurance over $50,000

D-  Elective deferrals to a section 401(k) cash or deferred arrangement

E-  Elective deferrals under a section 403(b) salary reduction agreement

F-  Elective deferrals under a section 408(k)(6) salary reduction SEP

G- Elective deferrals and employer contributions (including nonelective deferrals) to a section 457(b) deferred 

H- Elective deferrals to a section 501(c)(18)(D) tax-exempt organization plan. See "Adjusted Gross Income" in the Form 1040 instructions for how to deduct.

J-Nontaxable sick pay (information only, not included in boxes 1, 3, or 5)

K- 20% excise tax on excess golden parachute payments. See "Total Tax" in the Form 1040 instructions.

L- Substantiated employee business expense reimbursements (nontaxable)

M- Uncollected social security or RRTA tax on taxable cost of group-term life insurance over $50,000 (former employees only). See "Total Tax" in the Form 1040 instructions.

N- Collected Medicare tax on taxable cost of group-term life insurance over $50,000 (former employees only). See "Total Tax" in the Form 1040 instructions.

P- Excludable moving expense reimbursements paid directly to employee (not included in boxes 1, 3, or 5)

Q- Nontaxable combat pay. See the instructions for Form 1040 or Form 1040A for details on reporting this amount.

R- Employer contributions to your Archer MSA. Report on Form 8853, Archer MSAs and Long-Term Care Insurance Contracts.

S- Employee salary reduction contributions under a section 408(p) SIMPLE (not included in box 1)

T- Adoption benefits (not included in box 1). You must complete Form 8839, Qualified Adoption Expenses, to compute any taxable and nontaxable amounts.

V- Income from exercise of nonstatutory stock option(s) (included in boxes 1, 3 (up to social security wage base), and 5)

W- Employer contributions to your Health Savings Account. Report on Form 8889, Health Savings Accounts (HSAs).

Y- Deferrals under a section 409A nonqualified deferred compensation plan.

Z- 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. See "Total Tax" in the Form 1040 instructions.

AA- Designated Roth contributions to a section 401(k) plan.

BB- Designated Roth contributions under a section 403(b) salary reduction agreement.

For more information, see Form W-2 instructions