W-2 Form Box-by-Box Explained: What Every Number Means
Complete breakdown of every box on your W-2 form. Learn what Box 1 through Box 20 mean, how to check for errors, and what to do with your W-2 at tax time.
JustPayStubs Team
Updated February 1, 2026
The Numbered Boxes
Box 1: Wages, Tips, Other Compensation
Your total taxable wages for the year. Pre-tax deductions like 401(k) contributions and health insurance premiums are subtracted from this number.
Box 2: Federal Income Tax Withheld
The total federal income tax your employer withheld. This determines whether you get a refund or owe taxes when you file.
Box 3 & 4: Social Security
Box 3 is wages subject to Social Security tax (capped at $176,100 for 2025). Box 4 should be exactly 6.2% of Box 3.
Box 5 & 6: Medicare
Box 5 is Medicare wages (no cap). Box 6 should be 1.45% of Box 5.
Box 12: Various Codes
| Code | Meaning |
|---|---|
| D | Traditional 401(k) contributions |
| DD | Health insurance cost (employer-paid, informational only) |
| W | HSA employer contributions |
| AA | Roth 401(k) contributions |
| C | Taxable cost of group-term life insurance over $50,000 |
Boxes 15-20: State and Local Tax Info
| Box | Meaning |
|---|---|
| 15 | State abbreviation + employer's state ID |
| 16 | State wages |
| 17 | State income tax withheld |
| 18 | Local wages |
| 19 | Local income tax withheld |
| 20 | Locality name |
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