Learning how to read a W-2 is mostly learning which box answers which question: the same four questions, repeated for federal, Social Security, Medicare and your state. The form itself is one page of numbers that has to agree with everything your pay stubs said during the year.
What the form is, and when it arrives
Form W-2, Wage and Tax Statement, is the annual summary an employer sends to each employee and files with the tax authorities. It covers one calendar year of one employment relationship, and the deadline for furnishing it to you is 31 January. One form per employer: two jobs in a year means two forms, and a mid-year switch means two as well, which is the most common reason the totals on a return do not match the pay stubs you remember.
It is a different document from a pay stub in kind, not just in length — pay stub, W-2 and 1099: three documents, three jobs is the page for that comparison, including which record a given question belongs to.
The boxes, in order
The top of the form is identity: employee name, address, Social Security number, and the employer’s name, address and Employer Identification Number. Errors there are the ones that cause the most downstream trouble, because the Social Security number is how the wage record finds you.
Federal wage and tax boxes
| Box | As printed | What it holds |
|---|---|---|
| 1 | Wages, tips, other compensation | Taxable pay left after pre-tax items — the figure your return starts from |
| 2 | Federal income tax withheld | Federal tax already paid on your behalf during the year |
| 3 | Social Security wages | Wages the Social Security tax was computed on, up to the annual wage base |
| 4 | Social Security tax withheld | The employee share of that tax |
| 5 | Medicare wages and tips | Wages the Medicare tax was computed on — this base has no cap |
| 6 | Medicare tax withheld | The employee share, including the additional amount on higher earnings |
| 7 | Social Security tips | Reported tips that were counted for Social Security |
| 8 | Allocated tips | Tips an employer assigned to you under the allocation rules; rare |
| 9 | Not used | Left blank on purpose; it was retired years ago |
| 10 | Dependent care benefits | Benefits paid through a workplace dependent-care program |
| 11 | Nonqualified plans | Deferred compensation outside a qualified plan |
Box 12, and the codes that carry its meaning
Box 12 is up to four pairs of a letter and an amount, and the letter is the whole message. The ones that appear on ordinary wage statements:
- D — contributions to a traditional 401(k)-type plan you elected.
- W — contributions an employer made to your health savings account.
- AA and AB — designated Roth contributions to a 401(k) or a 403(b).
- C — taxable employer payments of moving expenses; L — subsidy amounts; P — retirement plan contributions before 1987.
Every code, including the ones you will never see, is listed in the instructions for Form W-2. Box 13 holds checkboxes — retirement plan participation, a statutory employee, third-party sick pay — and a tick there changes how a return is filled in, so it is worth reading rather than skipping. Box 14 is free space: employers use it for things like union dues, state disability premiums or local deductions, with no standard label.
State and local boxes
Box 15 identifies each state or locality and the employer’s ID number in it, then the boxes after it repeat the pattern you already know: Box 16 is state wages and Box 17 the state income tax withheld from them, while Boxes 18 to 20 do the same for a city or school-district tax where one applies. Working in one state and living in another produces two sets of these boxes, and the credit-side paperwork on your return follows from them.
W-2 versus pay stub versus 1099
The three documents differ in scope, timing and who signs them:
| Pay stub | W-2 | 1099-NEC | |
|---|---|---|---|
| Covers | One pay period | One calendar year of employment | One calendar year of non-employee payments |
| Shows tax | What was withheld this period | What was withheld all year | Nothing — withholding is usually zero |
| Arrives | Each pay date | By 31 January | By 31 January |
| Who is it for | An employee | An employee | A contractor or other payee |
Notice what a W-2 does not carry: hours, rates, or the per-line breakdown that made up the year. That detail only exists on the stubs, which is why reading a pay stub line by line is the practical counterpart to this page — the stub is where you check whether the annual totals were built correctly.
Stack the year out of the stubs and the gap between the boxes is one line wide: 26 periods at $2,000 of gross, with a $100 pre-tax premium taken out of each one, so Box 1 reads $49,400 where the gross for the year was $52,000.
When something looks wrong
- Compare it against the year’s stubs. Box 1 should be close to the sum of the taxable-wage figures you were paid, and Box 2 to the sum of the federal withholding lines. A difference the size of one period usually means a missing or duplicated stub, not a filing error.
- Check the identity block before the money. A wrong name or Social Security number is a mismatch at the agency that receives it, and it is fixed by the same employer letter that fixes a box.
- Ask for a correction, do not make one. The employer files a Form W-2c and sends you the replacement; only the issuer can change the record. Filing from figures you adjusted by hand invites a matching notice later.
- Expect pre-tax plans to make boxes disagree on purpose. Box 1 is normally smaller than Boxes 3 and 5 exactly because 401(k) and benefit premiums left the taxable base first. This is the single most-reported “error” that is not one.
If you keep your own payroll records rather than waiting on a form, make the numbers you can see count: the field-by-field pay stub template shows which lines a period record should carry, the builder prints the earnings and withholding lines of a single period as you enter them, and the glossary defines wage base, FICA and the rest of the vocabulary above.
Frequently asked questions
When should the form arrive?
After the calendar year ends: employers deliver it by 31 January for the previous year, and one form covers one year of one employment. If it is late, the payroll contact is the first place to ask, because the underlying wage data already exists in their system and in your stubs.
Why is Box 1 smaller than Box 3 and Box 5?
Box 1 is wages left after pre-tax deductions, while Social Security and Medicare wages are normally measured before them. The three boxes start from the same pay and diverge by roughly the pre-tax lines, which makes the difference between them the most useful consistency check on the whole form.
What do the letters in Box 12 mean?
Each entry is a code plus an amount, and the code carries the meaning: D for traditional 401(k) contributions, W for employer HSA contributions, AA and AB for designated Roth contributions in a retirement plan. The full list lives in the instructions for the form, and the same code can appear on several lines.
A box on my form is wrong. What actually fixes it?
The employer files a correction — Form W-2c — and sends you the replacement copy; you do not adjust the original by hand, and a filing made from wrong figures carries the wrong figures into the return. Compare the corrected boxes against your final stub of the year before you file, since a change to withheld tax moves the return with it.
Does a W-2 replace keeping my pay stubs?
They answer different questions, so neither replaces the other. A W-2 summarises a year in one column per tax type; a stub shows how a single period was built, line by line. The guide comparing the three documents covers which record answers which question.