The IRS Form W-4 is used by your employer to determine how much of your paycheck will be withheld for state and federal taxes. Filling out the form correctly and updating it appropriately will help you avoid overpaying or owing taxes when you file your return.
You’ll most likely see this form when starting a new job. Keep reading to learn how to complete Form W-4.
What is IRS Form W-4?
As mentioned above, IRS Form W-4 tells your employer the amount of money to take out of your paycheck for federal and state taxes. When filled out correctly, it prevents you from overpaying or owing taxes.
How to complete Form W-4
Form W-4 was redesigned in 2020, removing allowances and exemptions. Instead of taking allowances, you can follow the steps listed below.
Step 1 – Enter your personal information. This includes your full name, current address, Social Security number, and filing status.
Step 2 – Enter multiple jobs or indicate that your spouse also works. If you both work, it’s important to come together and coordinate your forms.
Certain factors, like deductions and dependents, must only be accounted for on one spouse’s form. Otherwise, you may end up withholding too much or too little come tax time. This can result in an unexpected tax bill when you file your return.
Refer to the multiple jobs worksheet included with Form W-4 or use the IRS Tax Withholding Estimator to determine the most accurate withholding amount.
Step 3 – Claim dependents to show if you’re eligible for the Child Tax Credit or Child and Dependent Care Credit. Accurately reporting your dependents helps ensure the correct amount of federal income tax is withheld from your paycheck and may help you avoid unexpected tax adjustments when filing your return.
Step 4 – Indicate other adjustments (if necessary). In this section, you can account for additional sources of income, like interest, dividends, and retirement income. Any deductions apart from the standard deduction would be included here.
Step 5 – Sign the form and send it to your employer!
How do I fill out Form W-4 if I have two jobs?
Step 2 on Form W-4 lets you account for multiple jobs. It’s important to report all your earnings on a W-4, so the proper amount of income tax is withheld. If you have a side gig, are self-employed, or receive a Form 1099, you can include that additional income on your W-4 too.
Note: If you are married, Step 2 is also where you would indicate that your spouse works.
Who should fill out a W-4?
Every employee required to file income taxes must fill out a federal W-4 for tax withholding. Similarly, if you live in a state that collects income taxes and you meet the requirements to file taxes, you must complete a state W-4.
When should I update my W-4?
Anytime your personal or financial situation changes, you’ll want to make sure you are having enough income tax withheld from your paycheck. Here are five reasons you would need to give your W-4 an update:
• Your total household income increased: A change in total income might put you in a different tax bracket, and you could end up owing more in taxes than you expected. If your household is earning more income, consider updating your W-4.
• You started a side-gig: If you work two jobs, you can record both earnings on a single form: See step 2 of Form W-4. Income tax withholdings are calculated based on your total earnings, so if you don’t receive a Form W-2 from your side gig (say you get Form 1099 instead), you should still account for your additional income on your W-4.
• You or your spouse began a new job: When your partner starts a new job and is completing a new W-4, this is a good time to revisit your W-4. Married taxpayers filing a joint return will indicate this by checking the box in Step 1(c) of Form W-4. This box must be checked on both spouses’ W-4 forms.
• Your family situation changed: The amount you have withheld for tax may need to change when you have children, get married, or get divorced. If you didn’t make an adjustment after a major life event, do it as soon as possible. Waiting means there are fewer pay periods to withhold the necessary federal tax.
• The tax laws changed: The tax laws in America are subject to change, and some tax laws will even change every year. If there is a major tax law update (the last time this happened was in 2025 with the One Big Beautiful Bill), it could impact how much you owe for taxes and/or how much you get back in your refund. If your tax liability goes up due to the tax law changes, you could avoid a surprise tax bill by adjusting your withholding percentage ahead of the filing season.
How do I update my W-4 to adjust my tax withholding?
If you’ve had a change in income, family situation, or simply want more (or less) tax withheld from your paycheck, you can update your W-4 even if you’re staying with the same employer.
Before filling out the form, consider why you’re updating it. Some common reasons include wanting more taxes withheld, getting married or getting divorced, having a child, or starting a second job.
Adjusting your withholding percentage is simple:
- Estimate how much income tax should be withheld from your paycheck each pay period using the IRS Withholding Calculator.
- Complete Form W-4. The W-4 can be adjusted anytime during the year. You can simply ask your employer for a new form or download one here. Use the following steps to fill out the form:
- Enter your personal information
- Enter multiple jobs or indicate that your spouse also works
- Claim dependents
- Indicate other adjustments (optional)
- Sign the form
- If you haven’t been withholding enough money for income taxes, you can make an estimated payment. To do so electronically, use IRS Direct Pay or the Treasury Department’s Electronic Federal Tax Payment System (EFTPS).
What happened to allowances on Form W-4?
Prior to tax year 2020, a withholding allowance number on your W-4 was used by your employer to determine how much of your income to withhold for state and federal taxes. Allowances were removed for tax year 2020 because of a large increase to the standard deduction.
Do I need to fill out a state W-4?
If you don’t live in Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, or Wyoming, you may have to complete a separate W-4 for the state in which you reside. This form serves the same purpose as the federal W-4, but to withhold state income. Visit your state’s department of revenue website for information on completing a state W-4.
State W-4 is used for state income tax withholding. Some states use information similar to the federal W-4, while others have their own rules and questions. Most state forms will ask for basic information like your full name, address, Social Security number, and filing status. It will also ask about whether you want additional state tax withheld, if you have dependents, or if you qualify for certain state tax exemptions or credits.
Many states still use allowances on their state tax withholding forms, even though the federal W‑4 no longer does. Other states have moved away from allowances and instead follow a system similar to the new federal form, so it’s worth checking your state’s specific rules to know exactly what applies to you.
How often should I check or adjust my W-4?
As a rule of thumb, you should reevaluate your withholdings when you get a new job, start a side hustle, or you’re in the midst of a big life change, like having a baby or getting married. When you want to adjust your withholdings, contact your employer.
