Form W-4, officially called the Employee's Withholding Certificate, is a form employees complete and give to their employer to determine how much federal income tax should be withheld from each paycheck.
The information provided on a W-4 helps employers calculate withholding so the right amount of tax is paid to the IRS throughout the year. Proper withholding can help reduce the chances of owing a large tax bill or receiving an unexpectedly large refund when you file your tax return.
Why Form W-4 Matters
Your W-4 directly affects how much federal income tax is withheld from your wages.
If too little tax is withheld, you may owe additional tax when you file your return. In some cases, underpayment penalties could also apply.
If too much tax is withheld, you may receive a larger refund, but you'll have had less money available in your paychecks throughout the year.
For many taxpayers, the goal is to have withholding that closely matches their expected tax liability.
When Should You Complete a W-4?
You'll generally complete a Form W-4 when:
- Starting a new job
- Beginning employment with a new employer
- Returning to work after a long absence
- Experiencing significant life or financial changes
Your employer uses the information from the W-4 to determine your federal income tax withholding going forward.
When Should You Update Your W-4?
It's often a good idea to review your withholding whenever a major life event occurs.
Common reasons to submit a new W-4 include:
- Getting married
- Getting divorced
- Having or adopting a child
- Purchasing a home
- Starting a second job
- Taking on freelance or self-employment income
- A significant increase or decrease in income
- Changes in tax credits or deductions you expect to claim
Updating your W-4 can help prevent surprises at tax time.
How Form W-4 Affects Your Tax Return
Your W-4 doesn't determine how much tax you owe. Instead, it determines how much tax is prepaid through paycheck withholding.
When you file your tax return, your actual tax liability is calculated based on:
- Your income
- Filing status
- Deductions
- Tax credits
- Other tax-related information
Your withholding is then compared to your final tax liability.
Possible outcomes include:
- Withholding exceeds tax liability → Refund
- Withholding equals tax liability → No refund and no balance due
- Withholding is less than tax liability → Balance due
What Information Is Included on Form W-4?
The current W-4 allows employees to provide information that makes withholding more accurate.
Depending on your situation, you may enter information about:
- Filing status
- Multiple jobs
- Dependents
- Other income
- Additional deductions
- Additional withholding amounts
Not every employee will need to complete every section.
Claiming Dependents and Credits
The W-4 allows eligible employees to account for certain tax credits, such as credits for qualifying children and other dependents.
Generally:
- Claiming qualifying dependents may reduce withholding.
- Claiming fewer credits may increase withholding.
- Requesting additional withholding increases the amount withheld from each paycheck.
The goal is to align withholding more closely with your expected tax liability.
Multiple Jobs and Working Spouses
Tax withholding becomes more complex when:
- You work more than one job
- You and your spouse both work
- You have substantial income from multiple sources
The W-4 includes options to help account for these situations so withholding remains accurate throughout the year.
Without adjustments, taxpayers with multiple sources of income sometimes find that too little tax has been withheld.
Can You Request Extra Withholding?
Yes.
Some employees choose to have additional federal income tax withheld from each paycheck.
Common reasons include:
- Self-employment income
- Investment income
- Side jobs or gig work
- Anticipated tax liability not covered by regular withholding
Requesting additional withholding can help reduce the likelihood of owing tax when filing your return.
W-4 vs. Other Common Tax Forms
Several forms beginning with the letter "W" serve different purposes.
Form W-4
- Used by employees
- Determines federal income tax withholding
- Given to an employer
Form W-2
- Issued by employers at year-end
- Reports wages and taxes withheld
- Used to prepare a tax return
Form W-9
- Used by independent contractors and vendors
- Provides taxpayer identification information
- Not used to determine withholding
A simple way to remember the difference:
- W-4 = Withholding for employees
- W-2 = Wages and withholding reported at year-end
- W-9 = Taxpayer information for independent contractors and vendors
What Happens If You Don't Submit a W-4?
Employers generally must withhold federal income tax even if a W-4 isn't provided. In those situations, withholding may be calculated using IRS default rules, which could result in more tax being withheld than necessary.
Submitting an accurate W-4 helps ensure withholding better reflects your individual tax situation.
How Tax Software and the W-4 Work Together
A W-4 affects withholding during the year, while tax software calculates your actual tax liability when you file your return.
After entering income, deductions, and credits, the software compares:
- Total tax owed
- Total tax paid through withholding and other payments
This calculation determines whether you'll receive a refund or owe additional tax.