What goes on each line of the W4

The W4 form has five main sections where you enter information, plus a signature line at the bottom. The first section asks for your name, address, and Social Security number — this is straightforward identification. The second section is where you claim dependents (children and other relatives you support). The third section covers multiple jobs or a working spouse, which affects how much tax gets withheld. The fourth section is for other income and deductions. The fifth section is where you can request extra withholding if you want more tax taken out of each paycheck.

Most people only need to fill in sections one and two. If you have a second job, a spouse who works, or significant non-wage income, you'll use section three. Section four applies mainly to people with investment income or large deductions. Section five is optional and used only if you want to adjust your withholding beyond what the form calculates.

Key Takeaways

  • Your name, address, and Social Security number go in section one; your employer will have most of this already.
  • Section two is where you claim dependents — each dependent reduces the tax withheld from your paycheck.
  • Section three applies only if you have a second job, a spouse who also works, or both; skip it otherwise.
  • You can request extra withholding in section five if you expect to owe taxes at the end of the year.
  • The IRS provides a tax withholding calculator on its website to help you decide what to enter.

Section one: Personal information and filing status

Start by entering your full name exactly as it appears on your Social Security card. Then enter your Social Security number and current mailing address. On the same section, you'll select your filing status: single, married filing jointly, married filing separately, or head of household. Your filing status determines how much tax is withheld. Married filing jointly usually results in less withholding than married filing separately, so choose carefully if you're married.

If you're starting a new job, your employer will already have your name and address from your job application, but you still need to complete the form yourself. The IRS uses the information you provide on the W4 to verify it matches your tax return later, so accuracy matters.

Section two: Claiming dependents

A dependent is someone you support financially — typically your children, but also sometimes parents, siblings, or other relatives living with you. For each dependent, you reduce the amount of tax withheld from your paycheck. The more dependents you claim, the less tax comes out each week or month.

Enter the number of dependents in the box provided. If you have no dependents, enter zero. The form will calculate a dollar amount based on your dependents and your income, which reduces your withholding. Be honest about the number of dependents you actually support; claiming dependents you don't have can result in underpayment penalties when you file your tax return.

Section three: Multiple jobs or a working spouse

If you have only one job and your spouse doesn't work (or you're single with one job), leave section three blank. This section exists because the tax system assumes one income per person. When you have two jobs or both spouses work, the withholding calculation changes — you may owe more tax than the standard withholding covers.

If you have a second job, you have two options: use the IRS calculator (linked on the form) to determine what to enter, or simply request extra withholding in section five instead. Many people find it simpler to request an extra $10 or $20 per paycheck in section five rather than work through section three's calculation.

Section four: Other income and deductions

Section four applies if you have income the W4 doesn't account for — investment income, self-employment income, rental income, or significant itemized deductions. Most W4 filers skip this section. If you have a second income source or expect large deductions, you can enter an amount here to reduce your withholding, or request extra withholding to cover it.

If you're unsure whether section four applies to you, the IRS tax withholding calculator will tell you. You can also ask your tax preparer or contact the IRS directly at 1-800-829-1040.

Section five: Extra withholding

Section five lets you request additional tax withholding beyond what the form calculates. Enter a dollar amount per paycheck — $10, $50, $100, whatever you choose. This extra amount comes out of every paycheck and goes toward your tax bill. Many people use this line as a safety net: if you're unsure about your withholding or expect to owe taxes, requesting an extra $20 per paycheck is a simple way to avoid a surprise bill in April.

You don't need a reason to request extra withholding. It's purely optional and can be changed anytime by submitting a new W4 to your employer.

Signing and submitting your W4

Sign and date the form at the bottom. Your employer will keep the original and may send a copy to the IRS. You don't mail the W4 yourself — you give it to your employer's human resources or payroll department. If you're starting a new job, they'll usually ask for it on your first day or during onboarding.

Keep a copy for your records. If your situation changes — you get married, have a child, or take a second job — you can submit a new W4 anytime. Your employer will use the most recent one you've submitted.

Using the IRS tax withholding calculator

The IRS provides a free tax withholding calculator on irs.gov that walks you through questions about your income, dependents, and filing status, then tells you what to enter on your W4. This calculator is especially useful if you have multiple jobs, a working spouse, or significant other income. It takes about 10 minutes and removes the guesswork.

To find it, go to irs.gov and search for "tax withholding calculator" or "W4 calculator." You'll need recent pay stubs and your most recent tax return to use it accurately. If you don't have those handy, you can estimate based on what you expect to earn this year.

Frequently Asked Questions

What happens if I claim too many dependents?

If you claim more dependents than you actually support, too little tax will be withheld from your paycheck. When you file your tax return, you'll owe the difference plus potential penalties. The IRS compares the dependents you claim on your W4 to those on your tax return, so mismatches get caught.

Can I change my W4 after I submit it?

Yes. You can submit a new W4 to your employer anytime your situation changes — marriage, divorce, a new child, a second job, or any other reason. Your employer will use the most recent W4 you've submitted. There's no penalty for changing it.

Should I claim zero dependents to get a bigger refund?

Claiming zero dependents when you have dependents means more tax is withheld, which usually results in a larger refund. However, this is essentially giving the government an interest-free loan of your own money. It's more practical to claim your actual dependents and adjust your withholding in section five if you want a refund.

What if I'm married and my spouse also works?

You both need to complete a W4 for your respective employers. Use the IRS calculator or section three to account for both incomes, or simply request extra withholding in section five on one or both forms. Many couples request an extra $10–20 per paycheck on one person's W4 to cover the combined household tax liability.

Do I need to file a new W4 every year?

No. Your W4 stays in effect until you change it. However, major life changes — marriage, divorce, a new child, a significant raise, or a second job — are good reasons to review and update it. You can also update it if you consistently get a large refund or owe taxes each year.