What Is a W-4 Tax Form and How Do You Fill It Out?

To fill out a W-4, enter your name, address, Social Security number, and filing status in Step 1, then sign and date at Step 5. Steps 2, 3, and 4 are optional adjustments for multiple jobs, dependents, and other income or deductions. Your employer uses what you enter to calculate how much federal income tax to withhold from each paycheck, so the closer your entries match your real situation, the closer your withholding will land to what you actually owe.

The form goes to your employer’s payroll or HR department, not to the IRS. You can submit a new one any time your situation changes.

Step 1: Personal Information and Filing Status

Enter your name, address, and Social Security number, then check one filing status: single or married filing separately, married filing jointly (or qualifying surviving spouse), or head of household.¹ That choice tells your employer which standard deduction and tax brackets to use. Head of household gets a larger standard deduction ($24,150 for 2026) than single filers ($16,100).²

If you have one job, no dependents, and no significant income outside your paycheck, you can skip Steps 2 through 4 entirely. Sign at Step 5 and you’re done. Your withholding will be based on your filing status and the standard deduction alone.

Step 2: Multiple Jobs or a Working Spouse

Step 2 exists because each employer withholds as if its paycheck is your only income. When you have two jobs, or you’re married filing jointly and your spouse also works, that default underwithholds. The higher combined income lands in higher tax brackets than either employer knows about.

You have three ways to fix this:

Check the box in Step 2(c) if there are exactly two jobs total and the pay is roughly similar. Do the same on the W-4 for the other job.¹
Use the Multiple Jobs Worksheet on page 3 of the form, which produces an extra dollar amount to enter on line 4(c) based on your two highest-paying jobs.
Run the numbers through the IRS Tax Withholding Estimator at irs.gov. It’s the most accurate option and generates a pre-filled W-4 you can hand to your employer.³

Only fill out Step 2 on the W-4 for your highest-paying job. If you do it on both, you’ll double-count and overwithhold.

Step 3: Dependents

Step 3 lowers your withholding to reflect tax credits you expect to claim. For 2026, multiply the number of qualifying children under 17 by $2,200 and the number of other dependents by $500. Add the totals and enter the sum on line 3.¹ The reduction shows up in your take-home pay right away rather than as a refund later.

Use current numbers. The per-child amount rose from $2,000 to $2,200 starting in 2025, so older guides are out of date. Only include dependents you actually qualify to claim. Overstating dependents to shrink your withholding below what you’ll owe can trigger a $500 civil penalty for false withholding information.⁴

Step 4: Other Income, Deductions, and Extra Withholding

Step 4 has three optional lines for fine-tuning:

Line 4(a) is for income you expect to receive that won’t have taxes withheld, such as interest, dividends, or retirement distributions. Enter the annual amount and your employer will spread additional withholding across your paychecks.¹
Line 4(b) is for itemized deductions that exceed your standard deduction. The 2026 standard deduction is $16,100 for single filers and $32,200 for joint filers. Use the Deductions Worksheet on page 4 to figure the amount to enter.²
Line 4(c) is a flat dollar amount you want withheld from every paycheck on top of everything else. This is the catch-all for anyone who wants a bigger refund or has income that’s hard to estimate precisely.

Step 5: Sign and Date

Your signature makes the form valid, and it’s given under penalty of perjury. The $500 false-information penalty applies to entries that deliberately reduce your withholding below what you owe, not to honest estimates that miss slightly.⁴

Claiming Exempt From Withholding

If you had zero federal income tax liability last year and expect zero this year, you can write “Exempt” in the space below line 4(c). To claim exempt, complete only Steps 1(a), 1(b), and 5, and leave everything else blank.¹

The exemption doesn’t roll over. You have to submit a new exempt W-4 by February 15 each year, or your employer will start withholding as if you’re single with no adjustments.⁵ If February 15 lands on a weekend or holiday, the deadline moves to the next business day. Claiming exempt when you’ll actually owe tax is one of the fastest ways to draw IRS scrutiny.

What Happens If You Don’t Submit One

If you start a job and never turn in a W-4, your employer must withhold as if you’re single with no other entries on the form.¹ For most people that means too much tax comes out of each paycheck. You’ll get the excess back at tax time, but every paycheck in between is smaller than it needs to be. Even filling out just Step 1 and Step 5 gives you your correct filing status and avoids this default.

When to Submit a New W-4

You don’t need to file a new W-4 every year unless you claimed exempt. But a life change usually calls for one:

Marriage or divorce, which changes your filing status.
A new child or other dependent, which opens up the $2,200 or $500 credit on Step 3.
Starting a second job, or your spouse starting work, which triggers Step 2.
A significant change in non-wage income, which belongs on line 4(a).
Buying a home, if your mortgage interest and other deductions will exceed your standard deduction.

Turn the completed form in to payroll or HR. Your employer must put the new withholding into effect no later than the first payroll period ending on or after the 30th day after you submit it, though many process it within a pay cycle or two.⁵

The IRS Tax Withholding Estimator takes about 25 minutes and generates a pre-filled W-4 based on your answers. It doesn’t ask for your name, Social Security number, or bank details, and it doesn’t save your data.³

One Limit Worth Knowing About: Lock-In Letters

If the IRS decides your W-4 significantly understates your withholding, it can send your employer a lock-in letter. Your employer must then begin withholding at the rate the IRS specifies, typically single with no adjustments, within 60 days.⁶ Once a lock-in is in effect, your employer must disregard any new W-4 you submit that would decrease withholding.

You have 60 days from the date of the letter to contact the IRS, submit a corrected W-4, and provide documentation.⁷ Miss that window and the lock-in rate stays until the IRS approves a change. These letters are rare and usually follow a pattern of substantial underwithholding across multiple years, but once one is issued, filing a new W-4 alone won’t reverse it.

The W-4 only controls federal income tax. Most states with an income tax have their own withholding form, so ask HR whether you need to complete a state version as well.

1
Internal Revenue Service. Form W-4 – Employee’s Withholding Certificate
2
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
3
Internal Revenue Service. Tax Withholding Estimator
4
Office of the Law Revision Counsel. 26 US Code 6682 – False Information With Respect to Withholding
5
Internal Revenue Service. Topic No. 753, Form W-4, Employees Withholding Certificate
6
Internal Revenue Service. Understanding Your Letter 2800C
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Internal Revenue Service. Understanding Your 2802C Letter