What goes on each line of the W-4

The W-4 is a form you give your employer to tell them how much tax to take from your paycheck. It has six main sections, and you fill them in order from top to bottom. The form asks for your name, address, Social Security number, and filing status first — those are straightforward. Then it moves into the parts that actually change how much tax comes out: dependents, other income, and adjustments.

You do not need to do math on most of the form. The IRS provides a worksheet on the back, and most people either use that worksheet or leave the dependent and adjustment lines blank if their situation is simple. If you have a spouse who also works, or you have side income, or you claim dependents, the worksheet walks you through it line by line.

Key Takeaways

  • Line 1 asks for your name, address, and Social Security number — copy these exactly as they appear on your Social Security card.
  • Line 2 requires your filing status (single, married filing jointly, married filing separately, or head of household), which determines your tax bracket.
  • Lines 3 and 4 are for dependents and other income; most people leave these blank or use the IRS worksheet on the back to calculate them.
  • Line 5 is for extra withholding if you want more tax taken out, or a negative number if you want less — this is optional and rarely needed.
  • You sign and date the form, then give it to your employer's payroll department; changes take effect on your next paycheck.

Step 1: Personal information and filing status

Start with your full legal name, current address, and Social Security number. Use the name and number exactly as they appear on your Social Security card — mismatches can cause problems when you file your tax return later. If you have moved recently, use your current address, not your old one.

Line 2 asks for your filing status. Choose one: single, married filing jointly, married filing separately, or head of household. Your filing status determines your tax brackets and standard deduction. If you are married and both you and your spouse work, you will each fill out your own W-4 with your own filing status. Married filing jointly is the most common choice for married couples, but if you want to split withholding differently between paychecks, you can each choose a different status or adjust line 5 instead.

Step 2: Dependents and other income

Line 3 asks how many dependents you claim — usually children under 17 or other relatives you support. If you have no dependents, write zero. If you do, the IRS worksheet on the back of the form tells you how to calculate the withholding impact. The worksheet accounts for the child tax credit and other dependent credits, so your withholding goes down if you have dependents.

Line 4 covers other income: side jobs, rental income, interest, dividends, or anything else not from your main job. If you have no other income, leave it blank. If you do, the worksheet shows you how to calculate the tax impact. This matters because your employer only knows about the paycheck they are giving you, not about money you earn elsewhere, so you need to tell them to withhold extra if you have other income.

Step 3: Adjustments and extra withholding

Line 5 is for adjustments and extra withholding. Most people leave this blank. You would use it if you want your employer to take out more tax than normal (write a dollar amount), or if you have deductions that lower your tax (write a negative number). This line is rarely needed because the earlier lines usually handle the math, but it exists for situations the worksheet does not cover.

If you are not sure whether you need to adjust line 5, you can leave it blank and see what happens when you file your tax return. If you owed money or got a much smaller refund than you expected, you can fill out a new W-4 and ask your employer to withhold more. If you got a large refund, you can fill out a new W-4 and reduce withholding.

Step 4: Sign, date, and submit

Sign and date the form at the bottom. You must sign it — an unsigned W-4 is not valid. Write the date you are filling it out. Then give it to your employer's payroll or human resources department. Do not mail it to the IRS; your employer keeps it on file.

Your new withholding takes effect on your next paycheck, usually within one or two pay periods. If you need to change your W-4 later — because you got married, had a child, got a second job, or your income changed — you can fill out a new one and submit it to payroll anytime. Your employer will use the most recent W-4 you gave them.

Using the IRS worksheet if your situation is complex

The back of the W-4 has a worksheet for people with dependents, other income, or multiple jobs. If you have any of those, the worksheet walks you through calculating the numbers to put on lines 3 and 4. You do not submit the worksheet to your employer — you just use it to figure out what to write on the form itself.

The worksheet has separate sections for dependents, other income, and multiple jobs. Start with the section that applies to you, follow the steps, and write the result on the corresponding line of the form. If you have more than one job, both employers need a W-4, and the worksheet helps you split withholding between them so you do not over-withhold or under-withhold.

Common mistakes to avoid

The most common mistake is leaving line 2 blank or writing something that is not one of the four filing statuses. Your employer cannot process the form without a filing status. Another mistake is claiming zero dependents when you have them, which causes too much tax to be withheld and you get a large refund — that is your money, but you could have used it during the year instead of giving the government an interest-free loan.

A third mistake is not updating your W-4 when your life changes. If you get married, have a child, or get a second job, your withholding may no longer be correct. You can submit a new W-4 anytime — there is no penalty for changing it. Finally, do not sign the form in pen if your employer asks for a digital version; follow their instructions for how they want you to submit it.

Frequently Asked Questions

What if I do not know my filing status?

Your filing status is determined by your marital status on December 31 of the tax year. If you are single on that date, you are single. If you are married, you can file jointly or separately. Head of household applies if you are unmarried and pay more than half the costs of a home for yourself and a dependent. When in doubt, single or married filing jointly covers most situations.

Do I have to claim all my dependents on my W-4?

No. You can claim fewer dependents on your W-4 than you actually have, which causes more tax to be withheld. Some people do this if they want a larger refund or if they are not sure how many dependents they will claim on their tax return. You claim the actual number on your tax return, so the W-4 and your return do not have to match.

What happens if I do not fill out a W-4?

Your employer cannot legally pay you without a W-4 on file. If you do not submit one, they will ask you to fill it out before your first paycheck. If you refuse, they may treat you as single with no dependents, which usually results in more tax being withheld than necessary.

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

Yes. You can submit a new W-4 to your employer anytime. The new withholding takes effect on your next paycheck. There is no limit to how many times you can change it, and there is no penalty for doing so.

Should I claim zero allowances to get a bigger refund?

The W-4 no longer uses allowances — it uses dependents and income instead. But the idea is the same: if you claim fewer dependents than you actually have, more tax comes out and you get a larger refund. However, that refund is your own money that you could have used during the year, so most people claim the number of dependents they actually have.