Filling out a W-4 correctly ensures your employer withholds the right amount of federal income tax from each paycheck. The W-4, formally called the Employee's Withholding Certificate, is an IRS form you complete when you start a new job or when your financial situation changes. Withholding too little may result in a tax bill and possible penalty at filing time. Withholding too much gives the IRS an interest-free loan of your money. For the most current version, see the 2026 W-4 form guide.
What the W-4 Does and When to Complete It
Your employer uses the W-4 to calculate how much federal income tax to withhold from each paycheck and send to the IRS on your behalf. You are required to complete a W-4 when you start a new job. You are not required to update it annually, but the IRS recommends checking your withholding each year, especially after major life changes.
Life events that typically warrant a new W-4 include getting married or divorced, having a child, taking on a second job, starting or stopping freelance income, or buying a home. The IRS offers a free Withholding Estimator tool at irs.gov/W4app to help you determine the right settings before filling out the form. Understanding how many pay periods are in a year is useful context for calculating your withholding per paycheck. When tax season arrives, knowing how to get your W-2 online helps you reconcile what was withheld against what you actually owe.
Step 1 — Enter Your Personal Information
Step 1 is required for all employees. Enter your legal first name, middle initial, and last name in Box (a). Enter your home address in Box (b), and your Social Security number in Box (c).
In Box (c), check the appropriate filing status box: Single or Married filing separately, Married filing jointly or Qualifying surviving spouse, or Head of household. Your filing status is the most important factor affecting your default withholding rate. If you are single with one job and no dependents, you can complete only Steps 1 and 5 and skip the rest. For a full walkthrough of the current form, see the 2026 W-4 complete guide.
Step 2 — Account for Multiple Jobs or a Working Spouse
Complete Step 2 only if you hold more than one job at the same time, or if you are married filing jointly and your spouse also works. Skipping Step 2 when it applies may result in under-withholding.
The IRS offers three options to address multiple income sources: (A) use the IRS Withholding Estimator at irs.gov/W4app and enter the result in Step 4(c); (B) use the Multiple Jobs Worksheet on page 3 of the W-4 instructions; or (C) simply check the box in Step 2(c) if there are exactly two jobs with similar pay. Option (C) is the simplest but only accurate when both jobs pay roughly the same amount. Having multiple pay periods across two jobs can significantly affect your annual tax calculation. You can also review biweekly pay periods for 2025 if you are reconciling withholding for a prior tax year.
Step 3 — Claim Dependents
Step 3 reduces your withholding by accounting for the Child Tax Credit and Other Dependents Credit. Complete this step only on one W-4 — the one for your highest-paying job — to avoid under-withholding.
For each qualifying child under age 17, multiply the number of qualifying children by $2,000 and enter that total in the first box. For other dependents (such as a dependent parent or a college-age child who does not meet the under-17 threshold), multiply the number of other dependents by $500 and enter that total in the second box. Add both amounts and enter the sum on the total line in Step 3. If you're wondering what age a dependent can open credit, that's separate from the W-4 dependent calculation.
Steps 4 and 5 — Other Adjustments and Signature
Step 4 is optional and allows three additional adjustments. In Step 4(a), enter any other income not subject to withholding — such as interest, dividends, or self-employment income — so the IRS can withhold on it through your paycheck. In Step 4(b), enter deductions beyond the standard deduction if you plan to itemize, which will reduce your withholding. Use the Deductions Worksheet on page 3 of the W-4 instructions for this calculation. Learning how tax write-offs work can help you determine whether itemizing will produce a larger benefit than the standard deduction.
In Step 4(c), you may enter any additional flat dollar amount you want withheld from each paycheck — for example, if you want an extra $50 per check withheld. This is useful if you want a larger refund or know you have income not covered elsewhere, such as side income from freelancing. Step 5 is simply your signature and date. Sign the form and give the completed W-4 to your employer's payroll or HR department — do not send it to the IRS.
Frequently Asked Questions
How many allowances should I claim on my W-4?
The current W-4 (redesigned in 2020) no longer uses allowances. Instead, you enter dollar amounts for dependents and other adjustments. If you have a prior-version W-4 on file, you do not need to update it — but the IRS recommends reviewing your withholding whenever your situation changes. For the latest version and any 2026-specific updates, see the W-4 form 2026 guide.
What happens if I don't fill out a W-4?
If you do not submit a W-4, your employer is required by the IRS to withhold at the highest single rate with no adjustments, as if you are single with no other deductions. This usually results in more tax withheld than necessary. If you want to understand how different taxes work, that context can help you think through your total tax picture. You can also review what happens if you don't file your taxes when your withholding likely covered your entire liability.
How often should I update my W-4?
The IRS recommends updating your W-4 whenever you experience a major life change — marriage, divorce, birth of a child, a new job, significant income change, or purchasing a home. You can also update your W-4 at any time during the year, and the change will typically take effect within the next one or two pay periods. If you're starting a side hustle to make more money, that new self-employment income requires a W-4 update.
Can I claim exempt on my W-4?
You may claim exempt from federal withholding if you had no federal tax liability in the prior year and expect none in the current year. To claim exempt, write "Exempt" on the W-4 in the space below Step 4(c) and sign Step 5. Exempt status expires each year — you must refile by February 15 to maintain it.
Does the W-4 affect state income tax withholding?
No — the federal W-4 only affects federal income tax withholding. Most states have their own separate withholding form. Your employer's payroll or HR department can provide the correct state withholding form for your work state. To understand how income taxes differ from other levies, see how excise taxes differ from sales taxes.
Sources & References
- IRS — About Form W-4, Employee's Withholding Certificate — https://www.irs.gov/forms-pubs/about-form-w-4
- IRS — Tax Withholding Estimator — https://www.irs.gov/individuals/tax-withholding-estimator
- IRS — Publication 505, Tax Withholding and Estimated Tax — https://www.irs.gov/publications/p505
Last updated: April 28, 2026