What each box on your W2 means

Your W2 is a tax form your employer sends you every January showing how much you earned and how much tax was withheld. The form has 14 numbered boxes plus some unnumbered ones, and each box holds a specific piece of information the IRS needs. You do not have to understand every box — most people only need a handful — but knowing what each one contains helps you spot errors and file your taxes correctly.

The W2 comes in two parts: a copy for you to keep, and copies your employer sends to the IRS and your state. All copies show the same numbers. The form is divided into two sections: boxes 1 through 12 contain income and tax information, and boxes 13 through 20 contain additional details like retirement plan status or dependent care benefits.

Start by checking the name, address, and Social Security number at the top of the form. If any of these are wrong, contact your employer's payroll department and ask for a corrected W2. An error here can delay your refund or cause the IRS to match your return to the wrong person.

Key Takeaways

  • Box 1 (Wages, tips, other compensation) is the number you use to calculate your federal income tax and is usually the largest number on the form.
  • Box 2 (Federal income tax withheld) shows how much your employer already sent to the IRS on your behalf, which reduces what you owe or increases your refund.
  • Boxes 5 and 6 (Medicare and Social Security wages and tax) are separate from federal income tax and appear on every W2 even if you had no federal tax withheld.
  • Box 12 contains codes (like D, E, or AA) that flag special types of income or deductions, and you need to read the code letter to understand what the amount means.
  • If you worked in more than one state or had income that does not appear in Box 1, check boxes 18 through 20 for state and local tax information.

Boxes 1 and 2: Your wages and federal tax withheld

Box 1 shows your total wages, tips, and other compensation for the year before any deductions. This is the number you report as income on your federal tax return. It includes your regular salary or hourly pay plus bonuses, commissions, and tips you reported to your employer. It does not include health insurance premiums your employer deducted, contributions to a traditional 401(k), or other pre-tax deductions — those reduce your taxable income and appear elsewhere on the form.

Box 2 shows federal income tax your employer withheld from your paychecks and sent to the IRS. The amount depends on what you claimed on your W4 form when you started the job. If you claimed too many dependents or exemptions, your employer withheld too little and you may owe money when you file. If you claimed too few, your employer withheld too much and you will receive a refund. This box does not include Social Security or Medicare tax — those are separate.

Boxes 3 and 4: Social Security wages and tax

Box 3 shows your Social Security wages — the amount your employer used to calculate your Social Security tax. For most people this matches Box 1, but if you earned over the annual Social Security wage base (the limit changes each year), Box 3 will be lower because earnings above that limit are not subject to Social Security tax.

Box 4 shows the Social Security tax your employer withheld. This is a flat 6.2% of your Social Security wages. You can verify this by taking the number in Box 3 and multiplying it by 0.062. If the math does not match, contact your employer. Self-employed people pay both the employee and employer portion (12.4% total), but if you are a W2 employee, your employer pays the other half.

Boxes 5 and 6: Medicare wages and tax

Box 5 shows your Medicare wages — the amount used to calculate your Medicare tax. Unlike Social Security, there is no wage limit for Medicare, so Box 5 usually matches Box 1. If you earned over $200,000 (or $250,000 if married filing jointly), you may also owe an additional 0.9% Medicare tax, but that appears on your tax return, not on the W2.

Box 6 shows Medicare tax your employer withheld. This is a flat 1.45% of your Medicare wages. You can verify it by multiplying Box 5 by 0.0145. Like Social Security, your employer pays an equal amount on your behalf that does not appear on your W2.

Box 12: Special income and deductions with letter codes

Box 12 can contain multiple entries, each with a letter code that tells you what kind of income or deduction it is. The code letter matters because different codes mean different things for your tax return. Common codes include D (401(k) contributions), E (403(b) contributions), F (403(b) insurance premiums), and AA (designated Roth contributions). If you see a code you do not recognize, the IRS website has a full list, or you can ask your employer's payroll department what it means.

The amount next to each code is what you contributed or what your employer reported. For example, if Box 12 shows "D 5000", you contributed $5,000 to your 401(k) that year. These amounts reduce your taxable income on your federal return, so they are important to report correctly. If Box 12 is blank, you had no special income or pre-tax deductions beyond what appears in Box 1.

Boxes 13 through 20: Retirement plans, dependent care, and state taxes

Box 13 has three checkboxes: one for retirement plan participation, one for second job or other income, and one for statutory employee status. A checkmark in the retirement plan box means you were covered by your employer's pension or 401(k) plan that year. This affects whether you can deduct IRA contributions on your tax return, so check this box carefully if you also have an IRA.

Boxes 14 through 20 contain information specific to your situation. Box 14 is "Other" and may include things like union dues, educational information, or nontaxable combat pay. Boxes 18 through 20 show state and local income tax information if you worked in a state with income tax. If you worked in two states during the year, you will see two W2 forms, one for each state. Check these boxes against your own records to make sure the amounts match what you remember earning in each location.

How to spot errors on your W2

The most common errors are a wrong Social Security number, misspelled name, incorrect wage amounts, or tax withheld that does not match your paychecks. To check for errors, add up your gross pay from your last few paychecks and compare it to Box 1. The numbers should be very close — they may differ slightly if you received a bonus or had unpaid time off, but they should not be off by hundreds of dollars.

If you find an error, contact your employer's payroll or human resources department right away. Ask them to issue a corrected W2, which the IRS calls a Form W2-c. Your employer must send the corrected form to you and the IRS. Do not file your tax return until you have the corrected W2 — filing with wrong information can delay your refund or trigger an audit. If your employer refuses to correct the error, you can file a complaint with the IRS using Form 13909.

Frequently Asked Questions

What if I lost my W2 or did not receive it by February?

Contact your employer and ask them to resend it. By law, employers must send W2 forms by January 31. If your employer says they already sent it and you did not receive it, ask them to check the address on file. If the address is wrong, ask for a corrected W2. If your employer will not send you a copy, you can call the IRS at 800-829-1040 and request a wage and income transcript, which shows the same information the IRS received from your employer.

Do I need to attach my W2 to my tax return?

No. You report the information from your W2 on your tax return, but you do not mail the W2 itself to the IRS. Keep your W2 in your records for at least three years in case the IRS asks questions about your return. If you file electronically, the tax software reads the numbers you enter and transmits them to the IRS — your W2 stays with you.

What if Box 1 is different from what I expected?

Box 1 should match your total gross pay for the year. If it is lower than you expected, you may have had pre-tax deductions like 401(k) contributions or health insurance premiums that reduced it. If it is higher, you may have received a bonus or back pay. If you cannot explain the difference, ask your payroll department to walk you through the calculation. They can show you a year-to-date earnings report that breaks down every deduction.

Can I use my W2 to file my taxes myself, or do I need a tax professional?

If you have only W2 income and no other sources of income, you can file your taxes yourself using free tax software or by mailing a paper return to the IRS. If you have rental income, self-employment income, investments, or other complex situations, a tax professional can help make sure you report everything correctly and claim all deductions you are may have access to to.

What does it mean if my W2 shows income in Box 1 but nothing in Box 2?

It means your employer did not withhold any federal income tax from your paychecks. This can happen if you claimed exempt status on your W4, or if your income was low enough that no tax was required. When you file your return, you will report the income from Box 1, and the IRS will calculate whether you owe tax or are due a refund based on your actual tax liability for the year.