How do I read my W-2?

What the W-2 is

Form W-2, the Wage and Tax Statement, is the annual summary your employer files with the government and sends to you, reporting what you were paid and what was withheld during the calendar year. You should receive one from every employer you worked for during the year, generally early in the filing season, and the numbers on it flow directly onto your federal return. The IRS's filing overview covers what to do if a form is late or missing; the short version is that the obligation to report the income is yours even if the paperwork is slow.

The boxes that do the heavy lifting

• Box 1 — Wages, tips, other compensation. Your federally taxable wages. This is usually not your salary. Pre-tax items — traditional 401(k) contributions, certain health premiums, some flexible spending contributions — are subtracted before Box 1 is computed, which is why the number is often smaller than what you think of as your pay.
• Box 2 — Federal income tax withheld. Everything your employer sent to the IRS from your paychecks. This is the number that gets credited against your tax when you file; the mechanics behind it are covered in the withholding explainer.
• Boxes 3 and 5 — Social Security wages and Medicare wages. These use different definitions of wages than Box 1, because Social Security and Medicare taxes apply to a different base — most retirement-plan contributions that escape Box 1 are still counted here. Social Security wages are also capped at an annual limit set by law, while Medicare wages are not, so on higher incomes Box 5 can exceed Box 3.
• Boxes 4 and 6 — Social Security and Medicare tax withheld. The payroll taxes taken for those programs, separate from the income tax in Box 2.
• Box 12. A coded catch-all for items that need their own reporting — retirement contributions, employer health coverage cost, and others, each identified by a letter code. The codes are defined in the W-2 instructions; some are informational only, while others affect your return.
• Boxes 15 through 20. The state and local mirror of the federal boxes: state wages, state income tax withheld, and any local equivalents. These feed your state return, which is a separate filing from the federal one.

Why the three wage numbers rarely match

The most common W-2 confusion is that Boxes 1, 3, and 5 show three different "wages." That is by design: each box answers a different question — what is taxable for income tax, for Social Security, and for Medicare — and each program defines its base differently. Differences among the three are normal. What is worth checking is whether the numbers are plausible against your final pay stub of the year and whether your name and Social Security number are exactly right, since a mismatched SSN can hold up processing. Errors are fixed by the employer issuing a corrected form (a W-2c), which is a request you make to payroll, not to the IRS.

Where to go deeper

IRS Publication 17 explains how wage income and withholding are reported on the return itself, and the official instructions that accompany the W-2 define every box and code. If a W-2 never arrives or an employer will not correct an error, the IRS filing pages describe the process for proceeding — and for genuinely stuck cases, there is help available.