Understanding Your W-2 Form: What Each Box Means

What a W-2 shows and why you need it

Your W-2 is a form your employer sends you every January showing how much you earned in the previous year and how much tax was already taken out of your paychecks. The form has 14 numbered boxes, each reporting a different piece of information the IRS uses to match what you earned against what you already paid. You need this form to file your tax return because it's the official record of your income and withholdings — the IRS gets a copy too, so the numbers have to match.

The W-2 comes in multiple copies: one for federal taxes, one for state taxes (if your state has income tax), one for your records, and sometimes one for local taxes. Your employer is required to send it to you by January 31st. If you don't receive it by early February, contact your employer's payroll department or HR to request it.

Key Takeaways

• Box 1 shows your taxable wages for federal income tax; Box 2 shows federal tax already withheld from your paychecks.
• Boxes 3 and 5 show Social Security wages and tax withheld; Boxes 5 and 6 show Medicare wages and tax withheld.
• Box 12 lists additional items like pre-tax contributions to health insurance or retirement plans that reduce your taxable income.
• The boxes on the right side (state and local tax information) are only relevant if you live in a state or city with income tax.
• You enter the numbers from your W-2 into your tax return form, and the IRS compares them to the copy your employer filed.

Boxes 1 and 2: Federal wages and tax withheld

Box 1 shows your total taxable wages for federal income tax purposes. This is your gross pay (before any deductions) minus certain pre-tax contributions like health insurance premiums or retirement plan contributions. This is the number you'll use on your tax return to calculate how much federal tax you owe.

Box 2 shows the federal income tax your employer already withheld from your paychecks throughout the year. When you file your return, the IRS compares this amount to what you actually owe based on your income and filing status. If more was withheld than you owe, you get a refund. If less was withheld, you owe the difference.

Boxes 3 and 4: Social Security wages and tax

Box 3 shows your wages subject to Social Security tax. For most people, this is the same as Box 1, but it has a cap — in 2024, Social Security tax only applies to the first $168,600 of earnings. If you earned more than that, Box 3 will be lower than Box 1.

Box 4 shows how much Social Security tax was withheld from your paychecks. The rate is fixed at 6.2 percent of your Social Security wages. You don't need to do anything with this number on your tax return — it's reported separately to Social Security — but it's useful to verify that the right amount was taken out.

Boxes 5 and 6: Medicare wages and tax

Box 5 shows your wages subject to Medicare tax. Unlike Social Security, there is no income cap for Medicare tax, so this number is usually the same as Box 1. If you earned over $200,000 (or $250,000 if married filing jointly), an additional 0.9 percent Medicare tax applies, and that would show separately.

Box 6 shows how much Medicare tax was withheld. The standard rate is 1.45 percent of your Medicare wages. Like Social Security tax, this is reported separately and you don't enter it on your tax return, but you can verify the calculation is correct.

Box 12: Pre-tax deductions and other items

Box 12 is actually multiple lines, each with a letter code that identifies what the amount represents. Common codes include health insurance premiums (code DD), 401(k) contributions (code D), and dependent care account contributions (code W). These are amounts you contributed before taxes were calculated, which is why they reduce your taxable income in Box 1.

You don't enter Box 12 amounts on your tax return — they're already factored into Box 1. But if you contributed to a health savings account (HSA) or flexible spending account (FSA), you may need the information from Box 12 to file Form 8889 or other supporting forms. Check the code letter to understand what each amount represents.

Boxes 17, 18, 19, and 20: State and local taxes

If you live in a state with income tax, Box 17 shows your state wages and Box 18 shows state income tax withheld. If you live in a city with local income tax (common in Ohio, Pennsylvania, and a few other places), Box 19 shows local wages and Box 20 shows local tax withheld. You'll use these numbers on your state and local tax returns, not your federal return.

If you live in a state with no income tax (like Texas, Florida, or Wyoming), these boxes will be blank or show zero. If you worked in multiple states during the year, you may receive multiple W-2 forms, one for each state.

How to use your W-2 when filing your return

When you sit down to file your tax return — whether on paper or using tax software — you'll enter the information from your W-2 into the appropriate lines. Most tax software asks you to enter Box 1 (wages), Box 2 (federal tax withheld), Box 5 (Medicare wages), and Box 6 (Medicare tax). The software then calculates whether you're owed a refund or owe additional tax.

Keep your W-2 in a safe place for at least three years. The IRS can audit returns from previous years, and you'll need the original form to prove your income and withholdings if questions come up. If you file electronically, you don't need to mail the W-2 to the IRS, but you should keep it with your tax records.

What to do if your W-2 has an error

If you notice a mistake on your W-2 — wrong name, wrong Social Security number, wrong income amount, or wrong tax withheld — contact your employer's payroll or HR department immediately. They can issue a corrected W-2 (called a W-2c) and file it with the IRS. Don't file your tax return until you have the corrected form, because mismatched numbers between your return and the IRS copy can trigger a notice.

If your employer doesn't respond or you can't reach them, you can file your return using the incorrect W-2 and then file an amended return (Form 1040-X) once you receive the corrected form. But it's much simpler to get the correction before you file in the first place.

Frequently Asked Questions

What if I worked for multiple employers in one year?

You'll receive a separate W-2 from each employer. When you file your tax return, you enter the information from all of them — the software adds up your total wages and total tax withheld across all employers. This is important because withholding is calculated at each job independently, so you might owe additional tax or get a refund depending on your total income.

Why is Box 1 different from my gross pay?

Box 1 subtracts pre-tax deductions like health insurance premiums, 401(k) contributions, and dependent care account contributions. These reduce your taxable income. Your actual gross pay (before any deductions) may be higher, but Box 1 is what the IRS uses to calculate your tax.

Do I need to mail my W-2 to the IRS when I file?

No. Your employer files a copy with the IRS, and you keep yours for your records. If you file electronically, you don't send the W-2 anywhere. If you file on paper, you don't attach the W-2 either — just keep it with your records in case the IRS asks questions later.

What if I didn't receive my W-2 by February?

Contact your employer's payroll department first. If they can't locate it or you've already left the job, you can call the IRS at 800-829-1040 and request Form 4506-C, which lets you get a transcript of your wage information directly from the IRS. You can then file your return using that transcript.

Can I file my tax return before I receive my W-2?

You can file early if you have all the information you need from other sources, but it's risky. If your W-2 shows different income or withholding than what you reported, the IRS will send you a notice. It's safer to wait until you have the W-2 in hand so your return matches what your employer filed.