How to Fill Out Tax Withholding on Form W-4

Form W-4 tells your employer how much federal income tax to hold back from each paycheck, and filling it out correctly means you keep more of your pay through the year without owing a surprise bill at tax time. Learning how to fill out Form W-4 comes down to five numbered steps, though most people only need to complete Steps 1, 3, and 5. If you skip the form entirely, your employer defaults to withholding as if you were a single filer with no dependents or deductions, which usually takes out more than necessary.¹ The current version is always at IRS.gov.²

What to Have in Front of You

You need your Social Security number and your filing status: Single (or Married Filing Separately), Married Filing Jointly (or Qualifying Surviving Spouse), or Head of Household. Filing status changes which tax brackets apply and how large your standard deduction is, so picking the wrong one throws off every calculation after it.

Pull out your most recent federal tax return. It gives you a benchmark for expected income, deductions, and credits. If you have self-employment income, freelance work, or investment income, gather those numbers too; forgotten side income is one of the most common reasons people end up owing at tax time.

If your spouse also works, get their most recent pay stubs. Without that information, both employers apply the full standard deduction to each paycheck independently, and the household ends up under-withheld.

Step 1: Personal Information

Enter your full legal name, address, Social Security number, and filing status. That’s it for this step. The filing status box is the one place where a wrong click quietly miscalculates your withholding for the entire year.

Step 2: Multiple Jobs or a Working Spouse

Complete Step 2 only if you hold more than one job at the same time, or if you’re married filing jointly and your spouse also works. You have three options:

Use the IRS Tax Withholding Estimator at irs.gov/W4App. This gives the most accurate result because it factors in income already earned and taxes already withheld during the year.³
Fill out the Multiple Jobs Worksheet on page 3 of the form.
Check the box in Step 2(c) if there are only two jobs and they pay roughly the same amount. Simplest, least precise.

Skipping Step 2 when it applies is where most under-withholding starts. If two earners each let their employer treat them as the household’s only income, the full standard deduction gets applied twice and neither paycheck holds back enough tax.

Step 3: Dependents and Other Credits

Multiply the number of qualifying children under age 17 by $2,200 and enter the total on line 3(a). For other dependents, such as children 17 or older or qualifying relatives, multiply by $500 and enter that on line 3(b). Add the two and put the combined figure in Step 3.⁴ These credits reduce your withholding directly, putting the money in each paycheck rather than making you wait for a refund.

The $2,200 child tax credit reflects the increase from $2,000 under the One Big Beautiful Bill Act, effective in 2025 and indexed for inflation starting in 2026.⁵ If your income is high enough that the credit phases out, reduce the amount you enter, or use the estimator for a precise figure.

Step 4: Other Adjustments

Three optional lines, each for a specific situation.

Line 4(a) — other income. Non-wage income you expect during the year (interest, dividends, retirement distributions) that won’t have tax withheld elsewhere. Entering it here tells your employer to take a little extra from each paycheck to cover the tax on it.

Line 4(b) — deductions. Use this only if you plan to itemize and your deductions will exceed the standard amount for your filing status. Work through the Deductions Worksheet on page 4 to calculate the difference. For 2026, the standard deduction is $16,100 for single filers, $32,200 for married couples filing jointly, and $24,150 for head of household.⁶ Overestimating on this line means too little tax gets withheld.

Line 4(c) — extra withholding. A specific dollar amount to take out of each pay period on top of everything else. The blunt-force tool for people who consistently owe at tax time or who have hard-to-estimate income.

Step 5: Signature

Sign and date the form. Without a signature it’s not valid, and you’re certifying the information under penalty of perjury.⁴

Claiming Exempt from Withholding

You can claim complete exemption from federal income tax withholding if two things are true: you had no federal income tax liability last year, and you expect none this year.⁴ To claim it, write “Exempt” in the space below Step 4(c), complete Steps 1(a), 1(b), and 5, and leave Steps 2 through 4 blank.

Exempt status expires every year. You must submit a new W-4 claiming the exemption by February 15, or your employer starts withholding at the default rate. If February 15 falls on a weekend or holiday, the deadline shifts to the next business day.¹

Claiming exemption when you don’t qualify carries a $500 civil penalty per false statement, and the IRS can bill you directly without going through deficiency procedures.⁷ That’s on top of the tax and interest owed for under-withholding.

If You Start Partway Through the Year

The standard W-4 calculations assume you’ll earn your salary for a full 12 months. Start a new job in June, and your employer withholds as though your annual income were much higher than it will actually be, which over-withholds. The IRS recommends using the Tax Withholding Estimator when you fill out the form after the start of the year or expect to work only part of it.⁴ Have your recent pay stubs on hand so the tool can account for taxes already withheld, and revisit the form at the start of the next full year.

If You’re a Nonresident Alien

Different rules apply. You must check “Single or Married filing separately” in Step 1(c) regardless of your actual marital status, and you should write “nonresident alien” or “NRA” in the space below Step 4(c). Nonresident aliens can’t claim the standard deduction, so your employer withholds extra amounts based on tables in IRS Publication 15-T. You also cannot claim exemption from withholding, even if you would otherwise meet the conditions.⁸

Handing It In and When It Takes Effect

The completed form goes to your employer, not the IRS. Most companies use a digital payroll portal where you upload a PDF or enter the data directly. Smaller workplaces may want a signed paper copy for HR or accounting. Either way, make sure it’s signed; an unsigned form is invalid and your employer keeps withholding at the previous rate.

Once your employer receives a new or revised W-4, federal rules require them to put it into effect no later than the start of the first payroll period ending on or after the 30th day from the date they received it.¹ In practice, many employers implement changes within one or two pay cycles. Check your first pay stub after the change and confirm the federal income tax line matches what you expected. If it doesn’t, call payroll right away.

Employers must keep W-4s on file for at least four years after the tax becomes due or is paid, whichever is later.⁹ Keep your own copy of every W-4 you submit.

When You Have to Send a New W-4

You can submit a new W-4 any time, but the law actually requires one within 10 days when a change in your circumstances reduces the withholding you’re entitled to claim and you won’t have enough tax withheld for the rest of the year.¹⁰ Triggers include:

Filing status change, such as Married Filing Jointly to Single, Head of Household, or Married Filing Separately
A child aging out of the child tax credit or a qualifying dependent no longer meeting the requirements
Expected deductions dropping by more than $2,300 from what you claimed on your previous W-4
Credits other than the child tax credit dropping by more than $500
A spouse starting a new job, if you had used the Multiple Jobs Worksheet or the estimator to account for the other income
An expected increase of more than $10,000 in regular wages at a second or third job when you haven’t checked the Step 2(c) box

Changes that would increase your entitlement, like getting married or having a child, don’t carry a mandatory deadline. But delay costs you money through over-withholding. A good habit: revisit your W-4 in January and after any major life event.

State Withholding Is Separate

Form W-4 only controls federal income tax withholding. Most states with an income tax require their own arrangement, and about half of those have a separate state withholding form to fill out alongside the federal W-4. Some states accept the federal form for state purposes, and a handful have no income tax. Rules vary widely: some states use their own filing status definitions and credit structures, so what you put on the federal form won’t automatically carry over. If you live in one state and work in another, you may owe forms to both. Your employer’s payroll or HR office can tell you which state forms apply. When you submit a new federal W-4, use it as a prompt to check the state side too.

1
Internal Revenue Service. Topic No. 753, Form W-4, Employees Withholding Certificate
2
Internal Revenue Service. About Form W-4, Employee’s Withholding Certificate
3
Internal Revenue Service. Tax Withholding Estimator
4
Internal Revenue Service. Form W-4 (2026) – Employee’s Withholding Certificate
5
Internal Revenue Service. Child Tax Credit
6
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
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Office of the Law Revision Counsel. 26 USC 6682 – False Information with Respect to Withholding
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Internal Revenue Service. Supplemental Form W-4 Instructions for Nonresident Aliens
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Internal Revenue Service. Employment Tax Recordkeeping
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Internal Revenue Service. Publication 505, Tax Withholding and Estimated Tax