How to Read Your W2 Form Box by Box (Plain English)

How to read your W2 form box by box

Your W2 has more than 20 boxes, and most of them aren’t labeled in a way that explains what they actually mean. This guide walks through each one in plain English, so when you sit down to file your taxes (or just want to understand your own pay), you know exactly what every number represents and why some of them don’t match each other.

The single most common question people have about their W2 is why the wage numbers in different boxes don’t agree. We’ll answer that one first because it trips up almost everyone.

Quick reference: the boxes that matter most

Box 1: Federal taxable wages. The number your tax return starts with. Box 2: Federal income tax withheld. What your employer already sent the IRS. Box 3 and 5: Social Security and Medicare wages. Often higher than Box 1. Box 12: Codes for retirement, health insurance, and other items. The most confusing box. Boxes 15-17: State wages and state tax withheld.

If you only look at four boxes, look at 1, 2, 12, and 17. Those four cover most of what you need for filing.

Why your wage boxes don’t match

Before the box-by-box walkthrough, here’s the thing that confuses everyone: Box 1, Box 3, and Box 5 often show three different numbers, even though they’re all supposed to be your wages.

Here’s why. Box 1 (federal taxable wages) is reduced by your pre-tax deductions. If you contributed to a traditional 401(k), paid for health insurance pre-tax, or put money into an FSA or HSA, those amounts come out before Box 1 is calculated. So Box 1 is your gross pay minus those pre-tax items.

Box 3 and Box 5 (Social Security and Medicare wages) are calculated differently. 401(k) contributions reduce your Box 1 wages but not your Social Security and Medicare wages. So if you contributed $5,000 to your 401(k), your Box 3 and Box 5 will be roughly $5,000 higher than your Box 1. That’s not an error. That’s how the tax rules work.

This is the single most common “my W2 looks wrong” panic, and 95% of the time, it’s just pre-tax deductions doing exactly what they’re supposed to.

The lettered boxes (A through F): who you are

The top portion of the W2 identifies you and your employer.

Box A: Your Social Security Number. Check this carefully. A wrong SSN can delay your refund or misroute your earnings record with the Social Security Administration.
Box B: Your employer’s EIN (Employer Identification Number). This is the employer’s tax ID, the business equivalent of an SSN.
Box C: Your employer’s name, address, and ZIP code.
Box D: A control number. This is an internal payroll code your employer uses to track the form. It doesn’t matter for your taxes, and many employers leave it blank.
Box E and F: Your name and address. If your address is wrong here, it doesn’t invalidate the form. The IRS uses the address on your tax return, not the one on your W2. Still worth correcting for future mailings.

The numbered boxes: your money

Now the part that actually affects your taxes.

Box 1: Wages, tips, other compensation. This is your federal taxable income from this employer. It’s the number that flows onto your tax return as wages. As covered above, it’s your gross pay minus pre-tax deductions like traditional 401(k), pre-tax health premiums, FSA, and HSA contributions.
Box 2: Federal income tax withheld. This is how much federal income tax your employer already took out of your paychecks and sent to the IRS on your behalf. When you file, this amount is credited against your total tax bill. If too much was withheld, you get a refund. If too little, you owe.
Box 3: Social Security wages. The portion of your earnings subject to Social Security tax. This has an annual cap (the Social Security wage base), so high earners may see Box 3 maxed out at the cap even if they earned more. Box 3 typically does not get reduced by 401(k) contributions, which is why it’s often higher than Box 1.
Box 4: Social Security tax withheld. The Social Security tax taken from your pay, calculated as 6.2% of Box 3. You can check the math: Box 4 should be about 6.2% of Box 3. If it’s significantly off, ask payroll.
Box 5: Medicare wages and tips. The portion of your earnings subject to Medicare tax. Unlike Social Security, Medicare has no wage cap, so Box 5 is often the highest wage figure on your form. Like Box 3, it usually isn’t reduced by 401(k) contributions.
Box 6: Medicare tax withheld. The Medicare tax taken from your pay, calculated as 1.45% of Box 5 (plus an additional 0.9% on earnings above a high threshold for high earners). You can check: Box 6 should be about 1.45% of Box 5 for most people.
Box 7: Social Security tips. If you report tips to your employer, the tip amount subject to Social Security tax appears here. Most non-tipped employees see this blank.
Box 8: Allocated tips. Tips your employer allocated to you (common in food service). This is separate from tips you reported. If there’s an amount here, it’s not included in Boxes 1, 3, 5, or 7, and you may need to account for it when filing.
Box 9: This box is grayed out and unused on current W2 forms. Ignore it.
Box 10: Dependent care benefits. Money you set aside (or your employer provided) for dependent care, such as a dependent care FSA. Amounts up to the annual limit are typically tax-free; anything above gets added to your taxable wages.
Box 11: Nonqualified plans. Distributions to you from a nonqualified deferred compensation plan. Most employees see this blank. If you have it, it relates to deferred compensation arrangements, usually for higher earners or executives.
Box 12: The code box. This is the one that confuses everyone, so it gets its own section below.
Box 13: Three checkboxes. Statutory employee, retirement plan, and third-party sick pay. The “Retirement plan” box gets checked if you participated in an employer retirement plan during the year (which can affect your IRA deduction eligibility). The other two apply to specific situations most employees won’t encounter.
Box 14: Other. A catch-all box where employers report items that don’t fit elsewhere. Common entries include union dues, state disability insurance (SDI), after-tax retirement contributions, and various other deductions. The labels here vary by employer, so if you see something cryptic, ask payroll what it means.
Boxes 15 through 20: State and local taxes. Box 15 shows your state and the employer’s state ID. Box 16 is your state taxable wages. Box 17 is state income tax withheld. Boxes 18-20 cover local (city or county) wages and taxes if your area has them. If you worked in multiple states, you may have multiple lines here.

Box 12 codes explained

Box 12 uses letter codes to report specific items. There can be up to four entries (12a, 12b, 12c, 12d), and each has a code on the left and a dollar amount on the right. The code “D | 5000” means $5,000 with code D.

Here are the codes you’re most likely to see:

Code D: Your 401(k) contributions (traditional, pre-tax). This is one of the most common codes. The amount reduced your Box 1 wages.
Code DD: The total cost of your employer-sponsored health coverage (both your share and the employer’s share). This is informational only. It is not taxable and doesn’t affect your return. People often panic seeing a large number here, thinking they owe tax on it. You don’t.
Code W: Employer and employee contributions to your Health Savings Account (HSA). This counts toward your annual HSA contribution limit.
Code E: 403(b) contributions (common for nonprofit and education employees).
Code C: Taxable cost of group-term life insurance over $50,000. This amount is already included in Boxes 1, 3, and 5.
Code DD vs Code W: People mix these up. DD is health insurance premiums (informational). W is HSA contributions (counts toward your HSA limit). Different things.
Code AA: Roth 401(k) contributions (after-tax). Unlike Code D, these did not reduce your Box 1 wages.
Code BB: Roth 403(b) contributions.
Codes A, B, M, N: Uncollected Social Security or Medicare tax. If you see these, they represent taxes you still owe, usually from tips or group-term life. Don’t ignore them.
Code V: Income from exercising nonqualified stock options. This is already included in Box 1.

There are more codes (the IRS uses an alphabet from A to HH), but the ones above cover the vast majority of W2s. If you see a code not listed here, the IRS General Instructions for Forms W-2 and W-3 has the full list, or your tax software will prompt you on what to enter.

Quick self-check before you file

Run through this before you file your taxes:

Box A SSN is correct. A wrong SSN is the most consequential error.
Box 1 makes sense. Gross pay minus pre-tax deductions. If it’s wildly off, check with payroll.
Box 2 reflects your withholding. Compare to your final pay stub’s year-to-date federal withholding.
Box 12 codes are entered correctly in your tax software. Code D, DD, and W are the most common.
State info (Boxes 15-17) matches your state and your final pay stub.

If your W2 has a genuine error (wrong wages, wrong SSN, missing income), don’t file with it. Contact your employer’s payroll department and request a W2-C (corrected W2). Filing with bad numbers means amending your return later, which is more work than waiting for the correction.

What to do if you can’t find your W2 at all

If you haven’t received your W2 by mid-February, your employer is required to have made it available by January 31. Most companies provide it through an online payroll portal. The exact system depends on where you worked.

For company-specific W2 retrieval instructions, see the relevant guide for your employer, such as the Walmart W2 forms page, the Target W2 forms page, the Kroger W2 forms page, or the Home Depot W2 forms page. Each covers the specific portal and the steps for current and former employees.

If your employer’s portal isn’t working, you can request an IRS Wage and Income Transcript at irs.gov, which shows the same income data the IRS has on file. As a last resort, you can file Form 4852 as a substitute W2 using your final pay stub.

The bottom line

Most of your W2 is straightforward once you know that Box 1 is your taxable wages, Box 2 is what was already withheld, and the wage differences between boxes come from pre-tax deductions. Box 12 is the only genuinely confusing part, and the codes you’ll actually see are limited to a handful: D for 401(k), DD for health insurance cost (informational), and W for HSA contributions.

When in doubt, compare your W2 to your final pay stub’s year-to-date totals. They should line up closely. If they don’t, that’s your signal to call payroll and ask for a corrected form before you file.

How to Read Your W2 Form Box by Box (Plain English)