The difference between a W-2 and a W-4 comes down to direction and timing: a W-4 is the form you hand your employer when you start a job to tell them how much federal income tax to withhold from your paychecks, and a W-2 is the form your employer sends you after the year ends showing what you actually earned and what was withheld. The W-4 is your input at the beginning. The W-2 is the receipt at the end, and it’s what you use to file your tax return.
The Two Forms at a Glance
You fill out the W-4. Your employer fills out the W-2.
The W-4, officially the Employee’s Withholding Certificate, is forward-looking. It tells payroll how much federal income tax to subtract from each paycheck before the money reaches your bank account.1Office of the Law Revision Counsel. 26 USC 3402 – Income Tax Collected at Source The W-2, the Wage and Tax Statement, is backward-looking. It’s the final accounting of what you were paid over the calendar year and how much was already sent to the government on your behalf.2Office of the Law Revision Counsel. 26 USC 6051 – Receipts for Employees
Get the W-4 roughly right and the W-2 at year-end will show withholding close to what you actually owe. Get the W-4 wrong and the W-2 will make that clear, either as a surprise bill in April or a large refund that represents money you loaned the government interest-free all year.
What the W-4 Does
You complete a W-4 when you start a new job. The form walks you through five steps. Step 1 covers your name, address, Social Security number, and filing status. Step 2 accounts for multiple jobs or a working spouse so combined household withholding stays on track. Step 3 reduces your withholding by claiming the child tax credit and credits for other dependents. Step 4 lets you report non-wage income like freelance earnings, claim deductions above the standard amount, or request a flat dollar amount of extra withholding per paycheck.1Office of the Law Revision Counsel. 26 USC 3402 – Income Tax Collected at Source Step 5 is your signature.
If you never turn in a W-4, your employer doesn’t guess. They’re required to withhold as if you’re single or married filing separately with no credits or adjustments, which usually produces the maximum withholding for your income level.3Internal Revenue Service. Publication 15-T (2026), Federal Income Tax Withholding Methods
Filling out a W-4 by hand involves some educated guessing, especially with multiple income sources. The IRS offers a free online Tax Withholding Estimator that takes your actual numbers and tells you exactly what to enter in each step. The tool can even generate a pre-filled form you download and hand to payroll.4Internal Revenue Service. Tax Withholding Estimator FAQs
Claiming Exempt
Some workers can skip federal withholding entirely by writing “Exempt” on their W-4. You qualify only if you had zero federal income tax liability last year and expect zero again this year.5Internal Revenue Service. Form W-4 (2026) Employee’s Withholding Certificate The exemption isn’t permanent. It expires every February 15, and you have to submit a new W-4 claiming exempt status by that date or your employer will revert to withholding as if you’re single with no adjustments.6Internal Revenue Service. Topic No. 753, Form W-4, Employees Withholding Certificate
What the W-2 Shows
After the calendar year ends, every employer that paid you wages has to send you a W-2 summarizing everything that happened on the payroll side. It reports your total taxable wages, federal and state income tax withheld, Social Security wages up to the 2026 taxable maximum of $184,500, and Medicare wages.7Social Security Administration. Contribution and Benefit Base It also shows the Social Security and Medicare taxes your employer deducted.
You need the W-2 to file your federal tax return. The IRS already has these same numbers on file, so your return has to match. If withholding shown on the W-2 exceeds what you actually owe, the difference comes back as a refund. If it falls short, you pay the balance.
Boxes Worth Reading
The W-2 is organized into numbered and lettered boxes. A handful matter most:
- Box 1: total taxable wages, tips, and other compensation. This is the number that flows onto your tax return.
- Box 2: federal income tax withheld during the year. Compare this against your actual tax liability to see whether you’re getting a refund or owe more.
- Boxes 3 through 6: Social Security and Medicare wages and the taxes withheld for each.
- Box 12: letter-coded items. Code D shows pre-tax 401(k) contributions, Code AA shows Roth 401(k) contributions, and Code DD shows the total cost of employer-sponsored health coverage (not taxable, but reported).8Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026)
- Boxes 15 through 20: state and local tax information. If you worked in multiple states, you may see multiple entries here or receive separate W-2s from the same employer.
When to Update Your W-4
The W-4 stays on file until you replace it. That’s where problems creep in. Life changes and the old form keeps working from outdated instructions. The IRS recommends checking your withholding whenever you get married or divorced, have a child, buy a home, start a side job, or see a significant change in non-wage income like investment gains.9Internal Revenue Service. Tax Withholding: How to Get It Right A common trigger people miss: a spouse entering or leaving the workforce shifts combined household income, and the old W-4 no longer reflects reality.
Updating is simple. Fill out a new W-4 and give it to payroll. There’s no limit on how many times you can update during the year. If your marital status changes from married to single, federal law requires you to submit a new W-4 reflecting the change.1Office of the Law Revision Counsel. 26 USC 3402 – Income Tax Collected at Source
When Your W-2 Should Arrive
Employers must deliver your W-2 by January 31 following the tax year. For the 2026 tax year, that means January 31, 2027. The same deadline applies to filing copies with the Social Security Administration.10Social Security Administration. Deadline Dates to File W-2s If the date falls on a weekend or holiday, it shifts to the next business day.
If your W-2 hasn’t arrived by the end of January, contact your employer first to confirm it was sent and that they have your correct address. If you still don’t have it by the end of February, call the IRS at 800-829-1040.11Internal Revenue Service. If You Don’t Get a W-2 or Your W-2 Is Wrong The IRS will contact your employer on your behalf. The same process applies if the W-2 arrives with incorrect information. Ask for a corrected form (a W-2c), and if the fix hasn’t happened by the end of February, bring the IRS in.
If You’re a 1099 Contractor
Not every worker gets a W-2 or fills out a W-4. If a company classifies you as an independent contractor rather than an employee, you’ll receive a Form 1099-NEC instead.12Internal Revenue Service. When Would I Provide a Form W-2 and a Form 1099 to the Same Person Contractors don’t have income tax or payroll taxes withheld, so there’s no W-4 to configure. You pay those taxes yourself, usually through quarterly estimated payments. If you receive both a W-2 and a 1099-NEC from the same company in the same year, it typically means you did some work as an employee and other work as a contractor.
State Withholding Is Separate
The W-4 only handles federal income tax. If you live or work in a state with its own income tax, your employer will usually have you fill out a separate state withholding certificate, particularly after the federal W-4 was redesigned in 2020. Nine states have no state income tax at all, so workers there deal only with the federal W-4. At year-end, your employer issues a state equivalent showing your state wages and state tax withheld, which you’ll use for your state return.