W-2 Box 12 Codes for 2026: What Each Letter on Your Form Means

Overview

What Is Box 12 on Form W-2?

Box 12 is the reporting slot on Form W-2 for items that need their own line and a specific IRS letter code. Instead of one lump sum, Box 12 breaks compensation, elective deferrals, benefit costs, and a few uncollected taxes into individual entries. Each entry has two parts: an alphabetic code (A, B, C, D, and so on up through II, plus TA, TP, and TT for 2026) and the matching dollar amount.

The IRS assigns a fixed meaning to every letter. Code D always means an elective deferral into a section 401(k) plan. Code DD always means the cost of employer sponsored health coverage. Employers cannot invent their own Box 12 codes. If a value does not have an IRS assigned letter, it belongs in Box 14a instead.

Your Form W-2 shows Box 12 with four small sub boxes labeled 12a, 12b, 12c, and 12d. The label positions on the form do not have to match the code letter. An employer that only reports code D can enter it in slot 12a even though D is not the first code alphabetically.

Reading the form

How Do You Read a Box 12 Code and Amount?

Every Box 12 entry follows the same layout: the code letter to the left of the vertical line and the dollar amount to the right. If the employer is reporting a prior year make up contribution under USERRA, the year appears between the code and the amount. For example, D 24 2250.00 means a $2,250 elective deferral into a 401(k) plan for tax year 2024. A current year 2026 entry has no year: just D 7000.00.

The order of the codes does not matter. What matters is that the letter and amount are paired correctly. If you see a code that is not on the current IRS list, ask your payroll department, because the SSA will reject a form with an unrecognized code.

Full code list

What Are the Complete Box 12 Codes for 2026?

Here is every Box 12 code in the 2026 IRS instructions, in the same order the IRS prints them. Amounts are always in whole dollars and cents.

This is general information, not tax advice. For the definitive text of any code, open the current IRS instructions and use the calculator above to see how a deferral changes your take home pay.

2026 additions

Which Box 12 Codes Are New for 2026?

Public Law 119-21, enacted July 4, 2025, added three Box 12 codes that first appear on W-2s issued in January 2027 for the 2026 tax year.

• Code TA: Employer contributions to a Trump account under a section 128 program. Beginning July 4, 2026, employers may contribute up to $2,500 a year toward the $5,000 total annual contribution limit. The employer amount is excluded from the employee gross income when paid under a qualifying program.
• Code TP: Total cash tips reported by the employee to the employer. Cash tips are voluntary or charged customer tips, plus tips received through tip sharing. Mandatory service charges are not cash tips. The code TP amount is what the employee has reported to the employer; it is not the deduction figure on the return.
• Code TT: Total qualified overtime compensation. Only the extra portion above the regular rate goes into code TT. In a time and a half rate, that is the half portion. The related deduction on the individual return is limited to $12,500 (or $25,000 for married filing jointly) for tax years 2025 through 2028.

Codes TP and TT tie back to another 2026 change: a new Box 14b that carries the Treasury Tipped Occupation Codes for the tipped worker. See our page on W-2 Box 14a and Box 14b for how those two boxes work together.

Multiple W-2 rule

How Do Employers Report More Than Four Box 12 Codes?

Copy A of Form W-2 (the copy that goes to the Social Security Administration) has only four Box 12 slots. If an employee has more than four coded items, the employer issues a second Form W-2 with the extra codes. The additional W-2 is not marked Corrected because it is not a correction; it is a continuation. On employee copies produced with approved substitute forms, more than four items can be listed on the same page.

A common example: an employee has code D for 401(k) deferrals, code AA for Roth 401(k), code DD for employer health coverage, code W for HSA contributions, and code C for group term life over $50,000. That is five entries. The employer must produce two separate Copy A forms, four codes on the first and one on the second.

How a $95,000 Salary Fills Box 12 (2026)

A 45 year old employee earning $95,000 with a 10 percent 401(k) deferral, $1,000 in Roth 401(k), $2,000 in HSA contributions through payroll, and $9,600 in employer paid health coverage. All figures round to the nearest cent.

Impact on wages

Does the Box 12 Amount Change Your Take Home Pay?

Some Box 12 amounts already reduce Box 1 wages, so they do not owe tax again. Others are informational only. A few tell the IRS about tax that could not be collected.

• Reduces Box 1 wages: Codes D, E, F, G, H, S, AA, BB, EE (elective deferrals and designated Roth reductions where applicable), plus Code W for HSA contributions and Code P for qualified moving reimbursements paid to Armed Forces members.
• Not taxable, informational: Code DD (health coverage cost) is not taxable. Code J (nontaxable sick pay), Code Q (nontaxable combat pay), and Code II (Notice 2014-7 Medicaid waiver payments) are not in Box 1.
• Adds to income: Code C (group term life over $50,000) is included in Boxes 1, 3, and 5. Code V (nonstatutory stock option spread) is included in Box 1. Code Z is included in Box 1 and triggers an additional tax.
• Uncollected tax: Codes A, B, M, and N tell the IRS that the employer could not collect certain social security or Medicare tax; the employee owes it on Form 1040.

Fixes

What Should You Do If a Box 12 Code Looks Wrong?

Check the pay stub for the same tax year. Most Box 12 entries can be traced to a pay stub line: 401(k) deferrals map to code D, HSA contributions to code W, employer health coverage to code DD, and Roth 401(k) to code AA. If the sum on your last pay stub does not match Box 12, ask payroll before you file.

If the employer agrees there is an error, they must issue Form W-2c (Corrected Wage and Tax Statement) and file it with the SSA. Do not silently change the amounts on your Form 1040. If the employer refuses to fix it, you can contact the IRS at 800-829-1040 after February 14 and file Form 4852 as a substitute W-2.

For Code DD, remember it is not taxable. Some filers see a large employer health coverage number and worry they owe tax on it; they do not. Code DD is only reported so that you and the IRS can see the total cost of your employer sponsored health plan.

Official source

Where Is the Official Box 12 Code List Published?

The IRS publishes the current Box 12 code list each year inside the General Instructions for Forms W-2 and W-3. The 2026 edition, catalog number 25979S, is posted as iw2w3.pdf on IRS.gov. Pages 20 to 24 walk through every code with the IRS definition, and the Form W-2 Reference Guide for Box 12 Codes on page 32 gives a quick lookup chart.

Bookmark that PDF or the parent page at IRS.gov/FormW2. The IRS updates it in January to reflect legislative changes such as P.L. 119-21, which added codes TA, TP, and TT for 2026 and made the Box 14 split described in our companion guide.