Here are the codes for Box 12: * Code A – Uncollected Social Security or RRTA tax on tips. Include this amount as part of your total tax on Form 1040. * Code B – Uncollected Medicare tax on tips. Include this amount as part of your total tax on Form 1040. * Code C – Taxable benefit of group term-life insurance over $50,000. Already included as part of your taxable wages in Boxes 1, 3, and 5. * Code D – Non-taxable elective salary deferrals to a 401(k) or SIMPLE 401(k) retirement plan. * Code E – Non-taxable elective salary deferrals to a 403(b) retirement plan. * Code F – Non-taxable elective salary deferrals to a 408(k)(6) SEP retirement plan. * Code G – Non-taxable elective salary deferrals and non-elective employer contributions to a 457(b) retirement plan. * Code H – Non-taxable elective salary deferrals to a 501(c)(18)(D) tax-exempt plan. * Code J – Non-taxable sick pay. This amount is not included in taxable wages in Boxes 1, 3, or 5. * Code K – Excise tax (equal to 20%) on excess "golden parachute" payments. Include this amount as part of your total tax on Form 1040. * Code L – Non-taxable reimbursements for employee business expenses. * Code M – Uncollected Social Security or RRTA tax on taxable group term life insurance over $50,000 for former employees. Include this amount as part of your total tax on Form 1040. * Code N – Uncollected Medicare tax on taxable group term life insurance over $50,000 for former employees. Include this amount as part of your total tax on Form 1040. * Code P – Non-taxable reimbursements for employee moving expenses, if the amounts were paid directly to the employee. * Code Q – Non-taxable combat pay. Some individuals may elect to include combat pay when calculating their Earned Income Credit. * Code R – Employer contributions to an Archer Medical Savings Account. This amount should be reported on IRS Form 8853. * Code S – Non-taxable salary deferral to a 408(p) SIMPLE retirement plan. * Code T – Employer paid adoption benefits. This amount is not included in Box 1 wages. You must use IRS Form 8839 to calculate the taxable and non-taxable portion of these adoption benefits. * Code V – Income from the exercise of non-statutory stock options. This amount is already included as taxable income in Boxes 1, 3, and 5. See also, how to report stock options. * Code W – Employer contributions to your Health Savings Account. Report this amount on IRS Form 8889. * Code Y – Salary deferrals under 409A non-qualified deferred compensation plan. * Code Z – Income received under 409A non-qualified deferred compensation plan. This amount is already included in taxable wages in Box 1. This amount is subject to an additional tax of 20% plus interest as part of your total tax on Form 1040. * Code AA – After-tax contributions to a Roth 401(k) retirement plan. * Code BB – After-tax contributions to a Roth 403(b) retirement plan.