How to Read Your W-2, Box by Box (2026 Guide)

Your W-2 lands in January, and it’s a grid of numbered boxes, lettered fields, and cryptic codes. Most people glance at Box 1, copy Box 2, and file. But every box on that form means something, and a few of them explain mysteries you’ve probably wondered about, like why the wages on your W-2 don’t match your salary. Here’s a plain-English, box-by-box walkthrough, plus what to check before you file.

First, what a W-2 actually is

Your W-2, officially the Wage and Tax Statement, is the form your employer sends you (and the IRS and SSA) each year, summarizing what you earned and what was withheld. Employers must get it to you by January 31, and the numbers on it feed directly into your Form 1040. If you worked more than one job, you get one from each employer. So before you file, this is the document to understand.

The lettered boxes (a through f): your identity

The left side holds the identifying details:

Box a: your Social Security number. Check it carefully, an error here can hold up your refund.
Box b: your employer’s federal ID number (EIN).
Box c: your employer’s name and address.
Box d: a control number, an internal payroll code, often blank.
Boxes e and f: your name and address.

None of these affect your tax, but a wrong SSN or name is worth fixing before filing.

Boxes 1 and 2: the two everyone looks at

Box 1: Wages, tips, and other compensation. This is your federal taxable wage, and here’s the thing that confuses everyone, it’s usually lower than your salary. That’s because pre-tax deductions (traditional 401(k), pre-tax health premiums, FSA, HSA) are already subtracted. The full explanation is in this guide to taxable wages and why Box 1 isn’t your salary.

Box 2: Federal income tax withheld. This is the total federal income tax your employer already sent to the IRS on your behalf, based on your W-4. It’s a credit against your final tax bill, so if Box 2 is more than you owe, you get a refund.

Boxes 3 through 6: Social Security and Medicare

These four cover your FICA taxes, and they often don’t match Box 1, which trips people up.

Box 3: Social Security wages, capped at the 2026 wage base of $184,500. Importantly, 401(k) contributions are not subtracted here, so Box 3 is often higher than Box 1.
Box 4: Social Security tax withheld, which should equal 6.2% of Box 3 (a maximum of $11,439 in 2026).
Box 5: Medicare wages, with no cap at all.
Box 6: Medicare tax withheld, 1.45% of Box 5, plus the extra 0.9% Additional Medicare Tax on wages over $200,000.

If you want to know why these three wage figures (Boxes 1, 3, and 5) differ, it comes down to which deductions each tax allows, which is exactly how FICA works.

Box 12: the alphabet-soup codes

This is the box that generates the most questions, because it uses letter codes to report specific items, and there are more than 30 of them. You’ll only have the ones that apply to you. The common ones:

Code D: your traditional 401(k) contributions. This amount was already subtracted from Box 1, which is a big reason Box 1 is lower than your salary. (The 2026 employee limit is $24,500.)
Code DD: the total cost of your employer-sponsored health coverage, both your share and your employer’s. This one causes panic every year, but it’s purely informational and not taxable. It’s just reported for Affordable Care Act purposes.
Code C: the taxable cost of employer group-term life insurance over $50,000. This is imputed income, already included in Boxes 1, 3, and 5.
Code W: employer and employee contributions to your HSA.
Code AA: Roth 401(k) contributions. Unlike Code D, these do not reduce Box 1, because Roth money is after-tax.

New for 2026: because of the “no tax on tips and overtime” rules, employers now report qualified tips and qualified overtime on the W-2, so you may see new entries that support those deductions when you file. If a code has you unsure, the IRS instructions for Forms W-2 and W-3 list every one, and epaystubs has a complete guide to every W-2 box and Box 12 code.

Boxes 13 and 14: checkboxes and everything else

Box 13: three checkboxes, statutory employee, retirement plan, and third-party sick pay. The “retirement plan” box being checked can affect whether you can deduct a traditional IRA contribution.

Box 14: “Other,” a catch-all your employer uses for items that don’t have their own box, like state disability insurance (SDI), union dues, or after-tax contributions. Labels here vary by employer.

Boxes 15 through 20: state and local taxes

The bottom rows cover your non-federal taxes:

Box 15: your state and your employer’s state ID number.
Box 16: your state wages.
Box 17: your state income tax
Boxes 18 through 20: local wages, local income tax, and the locality name, if you pay a city or local tax.

If you live in a no-income-tax state, Boxes 16 and 17 may be blank.

How to check your W-2 before you file

Don’t just copy the numbers, take five minutes to verify them against your last pay stub of the year:

Your final YTD gross, minus pre-tax deductions, should roughly match Box 1. Here’s how to reconcile your W-2 wages to your pay stub.
Box 2 should match your total federal tax withheld for the year.
Boxes 4 and 6 should be 6.2% and 1.45% of Boxes 3 and 5.

Small rounding differences are normal. If something’s off by more than a few dollars, or your name or SSN is wrong, contact your payroll department and ask for a corrected W-2 (a W-2c). Matching your W-2 to your final pay stub is the easiest way to catch an error before it becomes a tax-time headache.

Keeping it real

A W-2 looks intimidating, but most of it is just reporting things you already saw on your pay stubs all year, now totaled up. The two boxes that matter most for filing are 1 and 2, and the rest either explain why Box 1 isn’t your salary or report specific benefits. You don’t need to memorize 30 codes. You just need to know that Box 1 is your taxable wage, the FICA boxes play by different rules, Box 12 codes explain your benefits, and it’s worth a quick check against your last stub before you file. Do that, and your W-2 goes from cryptic to clear.

Frequently asked questions

Why is Box 1 on my W-2 lower than my salary? Because Box 1 is your federal taxable wage, which subtracts pre-tax deductions like traditional 401(k) contributions and health premiums. Your full salary is reduced by those before it lands in Box 1.

What does Box 12 Code DD mean? Code DD is the total cost of your employer-sponsored health coverage, both your share and your employer’s. It’s informational only and not taxable, reported for Affordable Care Act purposes.

When should I get my W-2? Employers must furnish your W-2 by January 31 for the prior tax year. If you haven’t received it by early February, contact your employer.

What do I do if my W-2 is wrong? Contact your employer’s payroll department and request a corrected W-2, called a W-2c. Don’t file with a W-2 you know has an error in your wages, taxes, name, or Social Security number.

The short version

Your W-2 is the Wage and Tax Statement summarizing your year’s earnings and withholdings, due to you by January 31. Boxes 1 and 2 are the big ones, your federal taxable wages and the federal tax withheld. Boxes 3 through 6 cover Social Security and Medicare, and they often differ from Box 1 because a 401(k) lowers Box 1 but not your Social Security and Medicare wages. Box 12’s letter codes report benefits like your 401(k) (Code D) and health coverage cost (Code DD, informational only). Boxes 15 through 20 handle state and local taxes. Before you file, match the form to your final pay stub, and ask for a corrected W-2 if anything’s wrong.

This article is general information, not tax, legal, or financial advice. Tax forms, codes, and figures change and vary by situation, so confirm current details with the IRS and check your own circumstances with a qualified professional.