Boxes 12 and 14 are part of IRS form W-2. This is the standard form for reporting payments to employees when money has been withheld for taxes -- or would have been withheld, had the employee not claimed a withholding allowance or exemption. A separate W-2 form must be completed for each employee.
Box 12 Overview
Box 12 details a variety of payments, benefits and uncollected tax revenue, all of which can have consequences for the employee's tax liabilities. Each line in the box should contain the dollar amount for the relevant sum of money, plus a one-letter code indicating the type of payment. There is room in the box for listing multiple payments.
Box 12 Examples
The major types of payments covered in Box 12 are uncollected taxes on tips, the taxable cost of employer-provided life insurance, elective deferrals for retirement or other savings plans, sick pay, joining bonuses for new employees, stock option income and expense reimbursements. Only payments for which there is a specific one-letter code should be included in Box 12.
Box 14 Overview
Whereas Box 12 covers only specific categories of payment, Box 14 covers all other relevant payments that are not covered elsewhere on the form W-2. In most cases, the entries in Box 14 will mainly cover forms of income that the employee has earned that will not attract a tax liability.
Box 14 Types
Box 14 does not require codes, so clear, contextual details must be listed alongside amounts. Examples of amounts that may be listed in Box 14 include union dues, health insurance premiums, payments towards the employee's education and contributions to retirement plans that don't fall in a category and code for Box 12.
In some states, Box 14 will include details of some state or local taxes. This does not include state and local income taxes, which are detailed in Boxes 17 and 20, respectively.