Form W-4, Employee's Withholding Certificate, tells your employer how much federal income tax to withhold from your paychecks. It does not determine how much tax you owe, only how much is taken out in advance throughout the year.

When should I update my W-4?

Update your W-4 whenever you experience a life change: getting married or divorced, having a child, starting a second job, or if you consistently owe money or receive a large refund. You can update it at any time during the year.

How do I fill out Form W-4 if I have two jobs?

Use Step 2 on Form W-4. You have three options: use the IRS Tax Withholding Estimator online, use the Multiple Jobs Worksheet on page 3, or check the box in Step 2(c) if both jobs pay similar amounts. Only fill out Steps 3-4 on the W-4 for the highest-paying job.

Form W-4 Guide: How to Fill It Out (2026)

✓ Key Points

Form W-4 tells your employer how much federal income tax to withhold from each paycheck
The current W-4 (redesigned in 2020) has 5 steps — most people only need to complete Steps 1 and 5
You can update your W-4 at any time during the year; changes typically take effect within 1-2 pay periods
Getting your W-4 right helps you avoid owing a large amount at tax time or giving the government an interest-free loan

What Is Form W-4?

Form W-4, officially titled "Employee's Withholding Certificate," is an IRS form that you fill out when starting a new job and can update at any time. It tells your employer how much federal income tax to withhold from your wages each pay period. The form does not determine your actual tax liability — it only controls advance payments toward that liability throughout the year.

When you file your tax return, the IRS compares what was withheld (shown on your W-2) against your actual tax owed. If too much was withheld, you receive a refund. If too little was withheld, you owe the difference and may face an underpayment penalty if the shortfall is significant.

The W-4 was significantly redesigned in 2020 and no longer uses "allowances." Instead, it uses a more straightforward approach with dollar amounts for adjustments.

Step-by-Step: How to Fill Out Form W-4

Step 1: Personal Information (Required)

Enter your name, address, Social Security number, and filing status. Your filing status determines your base withholding amount. Choose from:

Single or Married filing separately — Use this if you are unmarried, or married but filing a separate return
Married filing jointly — Use this if you are married and plan to file a joint return (this results in less withholding per paycheck)
Head of household — Use this if you are unmarried and pay more than half the cost of keeping up a home for a qualifying dependent

Step 2: Multiple Jobs or Spouse Works (If Applicable)

Complete this step only if you have more than one job at the same time, or if you are married filing jointly and your spouse also works. You have three options:

Option A: Use the IRS Tax Withholding Estimator at irs.gov (most accurate)
Option B: Use the Multiple Jobs Worksheet on page 3 of the W-4 form
Option C: Check the box in Step 2(c) if there are only two jobs and they pay roughly the same amount. This is the simplest option but may result in slightly higher withholding.

Important: If you choose Option B or C, do the same on the W-4 for the other job. Only complete Steps 3 and 4 on the W-4 for the highest-paying job.

Step 3: Claim Dependents (If Applicable)

If your total income will be $200,000 or less ($400,000 for married filing jointly), enter:

Line 1: Number of qualifying children under 17 x $2,000
Line 2: Number of other dependents x $500
Line 3: Add lines 1 and 2 — this is the total amount of credits claimed

These amounts reduce your withholding to account for the Child Tax Credit and Other Dependents Credit you will claim on your return.

Step 4: Other Adjustments (Optional)

Use this step to fine-tune your withholding:

4(a) Other income: Enter income not from jobs that you want withheld for (interest, dividends, retirement distributions). This increases withholding.
4(b) Deductions: If you plan to itemize deductions or claim above-the-line deductions beyond the standard deduction, enter the excess amount here. Use the Deductions Worksheet on page 3. This decreases withholding.
4(c) Extra withholding: Enter an additional dollar amount you want withheld from each paycheck. Use this if you want a larger refund or if you have additional tax liability from side income.

Step 5: Sign and Date (Required)

Sign and date the form. The W-4 is not valid without your signature. Submit it to your employer's payroll or HR department. You do not file Form W-4 with the IRS.

Common Scenarios

Scenario 1: Single with One Job, No Dependents

This is the simplest case. Complete Steps 1 and 5 only. Leave Steps 2, 3, and 4 blank. The default withholding based on your filing status will be close to correct.

Scenario 2: Married, Both Spouses Work

Complete Step 2 using one of the three options. The most accurate approach is using the IRS withholding estimator. If the jobs pay similar amounts, checking the box in 2(c) on both W-4s is the easiest option. Only claim dependents (Step 3) on the W-4 for the higher-paying job.

Scenario 3: Single with a Side Gig

If you have a W-2 job and also earn 1099 income, you have two approaches: (1) Complete Step 2 to account for the second income, or (2) Enter the estimated tax on your side income in Step 4(a) or add extra withholding in Step 4(c). Many people with side gigs prefer making quarterly estimated payments instead, especially if income varies.

How to Adjust for a Bigger or Smaller Refund

Want a bigger refund? Enter an additional withholding amount in Step 4(c). For example, entering $50 means an extra $50 per paycheck is withheld for federal taxes. Over 26 biweekly pay periods, that is $1,300 more withheld, resulting in a larger refund (assuming your tax liability stays the same). Keep in mind that a large refund means you gave the government an interest-free loan throughout the year.

Want a bigger paycheck (smaller refund)? Claim all deductions and credits you are entitled to in Steps 3 and 4(b). If you consistently receive a refund over $1,000, you may be over-withholding and could benefit from adjusting your W-4 to increase take-home pay.

When to Update Your W-4

Starting a new job — Required; your new employer needs a W-4 on file
Getting married or divorced — Your filing status and potentially your withholding rate changes
Having or adopting a child — You can claim the Child Tax Credit in Step 3
Starting or stopping a second job — Adjust Step 2 to account for multiple income sources
Buying a home — Mortgage interest may increase your deductions (Step 4b)
Receiving a large refund or owing a large amount — Adjust withholding to get closer to break-even
Major income changes — Raise, bonus, or income reduction warrant a W-4 update

You can submit a new W-4 to your employer at any time. Changes typically take effect within 1-2 pay periods. There is no limit to how many times you can update your W-4 during the year.

See How Withholding Affects Your Paycheck

Use our Paycheck Calculator to see your take-home pay after W-4 adjustments.

Paycheck Calculator

Form W-4 Guide: How to Fill It Out in 2026