A W-4 is a tax form you fill out for your employer. It tells them how much federal income tax to withhold from each paycheck.
The W-4 doesn’t determine how much tax you owe for the year, your tax return handles that. The W-4 decides how that tax is collected: in small amounts from every paycheck throughout the year.
Why Withholding Matters
The federal government expects taxes to be paid throughout the year, not just at filing time. Employers handle this by withholding a portion of your pay and sending it to the IRS on your behalf.
If your withholding is close to what you actually owe, you’ll get a small refund or owe a small amount when you file.
If too little is withheld, you may owe a larger amount when you file, and possibly an underpayment penalty if the gap is big enough.
If too much is withheld, you get a refund. A large refund sounds good, but it means you gave the government an interest-free loan for the year. You could have kept that money in your account and used it or saved it yourself.
The W-4 is one of the first things you fill out at a new job, and it directly affects your take-home pay on every paycheck. For more on the difference between your gross pay and what actually lands in your account, see Gross Pay vs Take-Home Pay.
How The Current W-4 Works
The IRS redesigned the W-4 in 2020, dropping the old allowances system and replacing it with five steps.
Step 1: Personal information and filing status (single, married filing jointly, head of household). Everyone must complete this step.
Step 2: Additional jobs or a working spouse. If you or your spouse have more than one job, this step adjusts withholding so the combined income is handled correctly. Skipping this when it applies often leads to under-withholding.
Step 3: Dependents. If you have children or other qualifying dependents, this step can lower withholding by accounting for the Child Tax Credit and other credits.
Step 4: Other adjustments. You can:
- Report other income that doesn’t have withholding (like freelance or investment income)
- Claim extra deductions beyond the standard deduction
- Request a specific additional dollar amount withheld each paycheck
Step 5: Signature and date. Required.
Steps 2 through 4 are optional. If you’re single with one job and no dependents, you only need to complete Steps 1 and 5. Your employer will withhold a standard amount based on your salary and filing status.
Common Situations
First job, single, no dependents: Fill in Step 1 with your personal info and “Single” filing status, then sign Step 5. That’s all most new workers need. Your employer will withhold a standard amount.
Multiple jobs: If you have two jobs at the same time, or you’re married and your spouse also works, withholding from each job separately often underestimates your total tax bill. Use the IRS’s online withholding estimator or complete Step 2 on your W-4 to adjust.
Freelance or gig income on the side: Gig income has no taxes withheld. You can add extra withholding from your main job using Step 4c to cover the tax on side income, or make quarterly estimated tax payments separately. See Are Side Gigs Worth It? for more on how side gig taxes work.
Major life changes: Update your W-4 after marriage, divorce, having a child, or a big income change. These events affect your tax situation and may mean your current withholding is off.
Large refund or large tax bill last year: Both mean your withholding was off. A large refund means too much was withheld. A large bill means too little. Either way, adjust your W-4 (or use the IRS estimator) to get closer to breaking even.
W-4 vs. W-2: What Is The Difference?
These two forms are related but very different:
| Form | What It Is | When You Get It |
|---|---|---|
| W-4 | Form you give your employer telling them how much to withhold | When you start a job (or want to update withholding) |
| W-2 | Form your employer sends you showing what you earned and paid in taxes | January or February each year, for tax filing |
The W-4 you fill out determines what ends up on your W-2. If your W-4 was off, the W-2 reflects that, and your tax return reconciles the difference.
What Happens If You Fill It Out Wrong
Filling out the W-4 incorrectly usually doesn’t trigger penalties by itself. The risk shows up at tax filing time.
If too little was withheld all year, you may owe money when you file, sometimes more than you expected. If the underpayment is large enough (generally more than $1,000 that wasn’t covered by withholding), there may also be an underpayment penalty.
You can submit a new W-4 to your employer at any time to adjust withholding going forward. It takes effect on future paychecks only, it doesn’t change withholding that has already happened.
The W-4 Is Not The Same As Your Tax Return
The W-4 is for your employer. Your tax return (filed annually on Form 1040) is where you report your total income, claim deductions and credits, and settle up with the IRS.
The W-4 controls how much is withheld each paycheck. The return determines what you actually owed for the year and whether your withholding was close. If your W-4 was set well, you break roughly even. If it was off, you get a refund or owe a balance. See How To File Income Taxes For The First Time for a walkthrough of that whole process.
Frequently Asked Questions
Q: What should I put on my W-4 for my first job?
For most first-time workers who are single with no dependents, filling in Step 1 with your name, address, and “Single or Married Filing Separately” status, then signing Step 5, is all you need. That tells your employer to withhold a standard amount. You can always adjust later.
Q: Will I get a refund if I fill out my W-4 correctly?
A correctly completed W-4 doesn’t guarantee a refund. It aims to match withholding to actual tax owed. A refund means more was withheld than you owed. The goal is to be close to even, a large refund means you over-withheld all year and left money with the government when you could have kept it.
Q: Can I claim exempt from withholding on my W-4?
Only if you owed no federal income tax last year and expect to owe none this year. Most workers don’t qualify. If you claim exempt incorrectly, you’ll likely owe a large amount when you file your return.
Q: How often should I update my W-4?
Review it when something changes: new job, marriage, divorce, birth of a child, major income change, or a significantly larger refund or tax bill than expected. There’s no requirement to update it annually, but checking it when your situation changes prevents surprises at tax time.