What goes on each line of the W-4

The W-4 has five main sections you fill in, plus signature lines at the end. Each section asks for different information: your name and address, your filing status, your dependents, your other income, and any extra tax you want withheld. The IRS redesigned the form in 2020, so if you last filled one out before then, the layout is different from what you remember.

You do not need to do math on the W-4 itself. The form walks you through what information to enter in each box, and your employer's payroll system uses that information to calculate how much tax to take from each paycheck. If you make a mistake on the form, you can fill out a new one at any time — there is no penalty for correcting it.

Key Takeaways

  • Line 1 asks for your full legal name, address, and Social Security number exactly as they appear on your tax return.
  • Line 2 requires your filing status (single, married filing jointly, married filing separately, or head of household), which determines your tax rate.
  • Lines 3 and 4 account for dependents and other credits, which reduce the amount of tax your employer withholds.
  • Line 5 is where you report other income sources like self-employment, rental income, or a second job, which increases withholding.
  • You can request extra withholding on line 4(c) if you want more tax taken out each paycheck than the standard calculation produces.

Step 1: Enter your personal information

Start with your full legal name on line 1(a). Use the name that appears on your Social Security card and your tax return — if you recently married or changed your name, update your Social Security record first, then use the new name on the W-4. Your employer will match this name to your Social Security number when they report your wages to the IRS.

On line 1(b), write your home address. This is where the IRS will send you notices if there is a problem with your withholding. On line 1(c), enter your Social Security number. Make sure all three pieces of information match what is on file with Social Security — mismatches can delay your tax refund or cause the IRS to send notices to your employer.

Step 2: Select your filing status

Line 2 asks you to check one box: single, married filing jointly, married filing separately, or head of household. Your filing status determines the tax brackets your employer uses to calculate withholding. If you are married and both spouses work, each of you fills out your own W-4 with your own filing status — you do not coordinate them through the form itself.

Head of household applies if you are unmarried and pay more than half the household expenses for yourself and a dependent. If you are unsure which status fits your situation, the IRS website has a filing status tool that walks through the rules. Using the wrong status means your withholding will be off, so it is worth checking before you submit the form.

Step 3: Claim dependents and credits

Line 3 asks for the total number of dependents you claim on your tax return. A dependent is usually a child under 17, a student under 24, or an adult relative you support financially. You enter the number, not the names. If you have no dependents, leave this line blank or enter zero.

Line 4 is for other credits: the child tax credit, the credit for other dependents, and education credits. The form provides a worksheet to calculate how much to enter here. If you claim these credits on your tax return, entering the amount on line 4 reduces your withholding — which means you take home more money each paycheck. If you do not claim these credits, leave line 4 blank.

Step 4: Report other income and adjustments

Line 5 is for other income that your employer does not know about: self-employment income, rental income, investment income, or a second job. If you have income from these sources, you enter an estimate of how much you will earn this year. Your employer uses this number to increase your withholding, because the IRS expects you to pay tax on all income, not just wages from this job.

If you have a spouse who works and you file jointly, you can also account for their income on line 5. The IRS worksheet on the form shows how to calculate the number to enter. If you have no other income, leave line 5 blank.

Step 5: Request extra withholding if needed

Line 4(c) lets you request that your employer take out additional tax from each paycheck, beyond what the standard calculation produces. You enter a dollar amount — for example, $50 per paycheck or $200 per month. This is useful if you know you will owe tax at the end of the year and want to avoid a large bill or a penalty.

Common reasons to request extra withholding: you have a side business that does not withhold taxes, you have investment income, you claimed too many dependents on a previous W-4, or you are married and both spouses work. You can change this amount at any time by submitting a new W-4.

Step 6: Sign and date the form

At the bottom of the form, sign and date it. You must sign for the form to be valid — your employer cannot process an unsigned W-4. Print your name below your signature. If you are married and filing jointly, only you need to sign; your spouse does not sign the form.

Give the completed form to your employer's payroll or human resources department. Keep a copy for your records. Your employer must start using the new withholding on your next paycheck, though some payroll systems take one or two pay periods to update.

Common mistakes to avoid

The most common error is entering the wrong filing status. If you are married and file jointly, both spouses should use "married filing jointly" on their own W-4s. If you both use "single," your employer will withhold too much tax, and you will get a large refund instead of taking home more money each month.

Another frequent mistake is leaving line 5 blank when you have other income. If you have a second job or self-employment income and do not report it on the W-4, your withholding will be too low, and you may owe tax when you file your return. The IRS worksheet on the form is designed to help you estimate this correctly.

A third error is claiming dependents you do not actually have. You can only claim a dependent on your W-4 if you claim them on your tax return. If you claim them on the W-4 but not on your return, the IRS will catch the mismatch and may penalize you.

Frequently Asked Questions

Can I change my W-4 after I submit it?

Yes. You can fill out a new W-4 at any time and give it to your employer. The new withholding takes effect on your next paycheck or within one or two pay periods, depending on your payroll system. There is no limit to how many times you can update it.

What if I do not have a Social Security number yet?

You cannot start work without a Social Security number. If you have applied for one, ask your employer if you can submit the W-4 once you receive it. If you are a noncitizen, you may have an Individual Taxpayer Identification Number (ITIN) instead, which you can enter on line 1(c).

Do I need to fill out a new W-4 every year?

No. Your W-4 stays in effect until you change it. However, you should review it each year if your situation changes — for example, if you get married, have a child, get a second job, or your income changes significantly. Major life changes are a good time to update your withholding.

What happens if I claim zero dependents and request extra withholding?

Your employer will withhold the maximum amount of tax from each paycheck. This means you will take home less money but will likely get a refund when you file your tax return. Some people do this intentionally if they want to avoid owing tax at the end of the year.

Can my employer refuse to accept my W-4?

Your employer must accept a valid W-4 that you sign and date. However, if the IRS sends your employer a notice that your withholding is incorrect, your employer must follow the IRS notice instead of your W-4 until you submit a corrected form.