What a W2 Form Is and Why You Fill It Out

A W2 form is the document your employer sends you each January showing how much you earned and how much tax was withheld from your paychecks during the previous year. You do not fill out a W2 yourself — your employer fills it out and sends it to you. What you do is read it carefully, check it for errors, and use the numbers on it when you file your tax return.

The W2 has six copies: your employer keeps one, the IRS gets one, your state gets one, and you receive copies for your records and to attach to your federal and state tax returns. If the numbers on your W2 do not match what you remember earning or having withheld, you need to contact your employer to request a corrected form before you file.

Understanding each line on the W2 matters because mistakes on it can delay your refund, trigger an audit, or cause you to pay more tax than you owe. The form looks complicated, but most lines are straightforward once you know what they measure.

Key Takeaways

  • Your employer fills out the W2, not you — you read it, check it for accuracy, and use it when filing your tax return.
  • Box 1 (wages, tips, other compensation) is the number you use to calculate your federal income tax; Box 2 is the federal tax already withheld.
  • If your W2 shows incorrect amounts, contact your employer when ready to request a corrected form (called a W2-c) before you file.
  • You must receive your W2 by January 31 each year; if it arrives after that date or you never receive it, you can request a transcript from the IRS.
  • Attach Copy B of your W2 to your federal tax return when you file; keep Copy C for your records.

The Main Boxes: Wages, Tax Withheld, and Gross Income

Box 1 (Wages, tips, other compensation) is the total amount of money you earned from your job before any deductions. This is the number you use to calculate how much federal income tax you owe. It includes your regular salary or hourly wages plus any bonuses, commissions, or tips your employer reported. It does not include money taken out for health insurance, retirement contributions, or taxes — those are subtracted separately.

Box 2 (Federal income tax withheld) shows how much money your employer already sent to the IRS on your behalf throughout the year. When you file your return, the IRS compares this number to the total tax you actually owe. If Box 2 is larger than what you owe, you get a refund. If it is smaller, you owe the difference.

Box 3 (Social Security wages) and Box 5 (Medicare wages) are usually the same as Box 1, but they can differ if you had certain types of income or deductions. These boxes determine how much Social Security and Medicare tax you paid. Most people do not need to do anything with these numbers — they are there so the government can track your Social Security and Medicare contributions.

Box 4 (Social Security tax withheld) and Box 6 (Medicare tax withheld) show the payroll taxes already taken from your paychecks. These are separate from federal income tax. You do not need to calculate these yourself; your employer withheld them automatically.

State and Local Tax Information

Box 19 (state income tax withheld) and the state wage boxes show what your employer sent to your state tax authority. If you live and work in the same state, this is straightforward. If you worked in multiple states or moved during the year, you may receive multiple W2 forms — one for each state where you earned income.

Some cities and counties also collect local income tax. If yours does, your W2 will show local tax withheld in Box 20 (local income tax withheld) and the local wage amount in Box 18. When you file your state and local returns, you will use these numbers the same way you use the federal boxes.

If you worked in a state with no income tax (such as Texas, Florida, or Nevada) but lived in a state that does tax income, you may owe tax to your home state even though nothing was withheld. Check your state's tax authority website or speak with a tax preparer if you are unsure.

Special Boxes for Retirement, Health Insurance, and Other Deductions

Box 12 contains codes and amounts for pre-tax deductions taken from your paycheck. Common codes include "D" for 401(k) contributions, "DD" for 403(b) contributions, and "EE" for employee health insurance premiums. These amounts reduce your taxable income, which is why they appear separately from Box 1. If you contributed to a retirement plan at work, you will see this box populated.

Box 14 is a catch-all for other information your employer wants to report — sometimes union dues, sometimes educational information, sometimes other employer-specific deductions. The label next to Box 14 tells you what the amount represents. You do not need to do anything with this information unless the label indicates it affects your taxes.

Box 11 (nonqualified plans) is rare and applies only if your employer offered a deferred compensation plan outside the standard 401(k) or 403(b) system. Most employees will see this box blank.

What to Do If Your W2 Contains Errors

Check your W2 against your final paystub from December. Box 1 should match the total wages shown on that paystub (or very close — sometimes the final paystub includes year-end adjustments). Box 2 should match the total federal tax withheld across all your paychecks for the year. If either number is significantly different, contact your employer's payroll or human resources department when ready.

Do not file your tax return with a W2 you believe is wrong. Instead, ask your employer to issue a corrected W2, called a W2-c (Corrected W2). Your employer has until February 28 to send corrected forms to you and the IRS. If you file before the correction arrives, you can file an amended return (Form 1040-X) once you receive the corrected W2.

If your employer refuses to correct the form or you cannot reach them, you can request a wage and income transcript directly from the IRS by calling 1-800-908-9946 or visiting irs.gov. The transcript shows what the IRS has on file for your earnings and withholding, and you can use it to file your return or to prove to your employer that the W2 is wrong.

When You Receive Your W2 and What Happens If You Do Not

Your employer must send you a W2 by January 31 each year for the previous calendar year. If you do not receive it by early February, contact your employer first — sometimes forms are mailed to an old address or delayed in the mail. If your employer says they sent it but you never received it, ask them to remail it or provide a duplicate.

If you have genuinely lost contact with your employer or they refuse to send a W2, you can request a wage and income transcript from the IRS. This document shows your reported wages and withholding and can be used in place of a W2 to file your return. You can order a transcript online at irs.gov, by phone at 1-800-908-9946, or by mail using Form 4506-C.

Do not file your return without a W2 or transcript if you received W2 income. Filing without it can trigger an IRS notice later asking you to provide proof of the income and withholding.

How to Use Your W2 When Filing Your Tax Return

When you file your federal return (Form 1040), you enter the numbers from your W2 into the appropriate lines. Most tax software walks you through this automatically — you type in the amounts from Box 1, Box 2, and any other relevant boxes, and the software places them in the correct spots on your return. If you file by hand, the Form 1040 instructions tell you which W2 boxes correspond to which return lines.

You must attach Copy B of your W2 to your federal return if you are filing by mail. If you file electronically, you do not attach the physical form, but you must keep it for your records. Keep all copies of your W2 for at least three years in case the IRS has questions about your return.

For state and local returns, follow the same process using the state and local wage and withholding information from your W2. Each state's tax authority provides instructions on which boxes to use.

Frequently Asked Questions

What if I worked for multiple employers during the year?

You will receive a separate W2 from each employer. When you file your return, you enter the wages and withholding from all of them. The IRS automatically adds them together to calculate your total income and total tax withheld. Make sure you attach all W2 copies to your return if filing by mail.

Can I file my tax return before I receive my W2?

No. You need the information on your W2 to file accurately. If your employer is late sending it, wait until you receive it before filing. If it is already late February and you still have not received it, contact the IRS to request a wage transcript, which you can use to file your return.

What does it mean if Box 2 shows more tax withheld than I expected?

Your employer withheld too much federal tax from your paychecks during the year. This usually happens if you claimed too few allowances on your Form W4 or if you had a major life change (marriage, second job, large bonus) that you did not report to payroll. The extra withholding means you will likely receive a refund when you file your return.

Do I need to do anything with the Social Security and Medicare boxes?

No. Boxes 3 through 6 are informational — they show what you and your employer paid into Social Security and Medicare. The IRS and Social Security Administration use these numbers to track your contributions. You do not enter them on your tax return.

What if my W2 shows income I did not earn or do not recognize?

Contact your employer when ready. This could be a data entry error, income from a job you forgot about, or a sign of payroll fraud. Your employer should be able to explain every amount on the form. If they cannot or refuse to, contact your state's labor department or the IRS.