Start with the basic information section

The first page of the W-4 asks for your name, address, Social Security number, and filing status. If you are married and filing jointly, select "Married filing jointly" in Step 1(c). This is the box that tells your employer how to calculate your withholding.

Both spouses can work, or only one. The form works the same way either way — you are just telling your employer how much federal tax to hold from your paychecks based on your household's total income and deductions. Your spouse will fill out their own W-4 at their job (if they have one), and the two forms work together to cover your joint tax bill.

Write your full legal name as it appears on your Social Security card. If you have changed your name since you got your card, update it with Social Security first — mismatches between your W-4 and your Social Security record can delay your refund or cause other problems.

Key Takeaways

  • Select "Married filing jointly" in Step 1(c) so your employer withholds the right amount for a joint return.
  • If both spouses work, each fills out their own W-4 at their own job, and you coordinate the total withholding between the two forms.
  • Step 2 asks about other jobs or income your spouse has — include it so your employer knows your household's full picture.
  • Step 3 covers dependents and other deductions; you claim them once on one spouse's W-4, not on both.
  • Use the IRS W-4 calculator or a worksheet to figure out the right withholding before you fill in Step 4.

Tell your employer about your spouse's income in Step 2

Step 2(b) asks whether your spouse has a job or other income. If your spouse works, enter their expected annual wages. If your spouse does not work or has no other income, leave this blank or enter zero.

This matters because your employer needs to know your household's total expected income to calculate withholding correctly. If you earn $50,000 and your spouse earns $50,000, your employer should withhold as if you are a household earning $100,000, not as if you are a single person earning $50,000. Leaving this blank can result in too little tax being withheld during the year and a bill when you file.

If your spouse is self-employed or has income from investments, rental property, or other sources, include that too. The goal is to give your employer a realistic picture of what your household will owe.

Claim dependents and deductions once, not twice

Step 3 is where you claim dependents — children, elderly parents, or other relatives you support. You claim each dependent once across both spouses' W-4 forms combined, not once on each form. If you have two children and your spouse also works, you might claim both children on your W-4 and zero on your spouse's, or split them between the two forms. The total across both forms should equal the number of dependents you actually have.

The same rule applies to Step 3(b), which covers other deductions. If you own a home and will itemize deductions on your tax return, or if you have significant charitable giving or student loan interest, you can account for that here. Again, you are doing this once for your household, not once per spouse.

If you are not sure whether you will itemize or take the standard deduction, use the IRS W-4 calculator (available at irs.gov). It walks through your situation and tells you what to enter.

Use Step 4 to adjust withholding if needed

Step 4 is optional and is where you make fine adjustments. If you expect to owe money when you file, or if you want a larger refund, you can have extra tax withheld from each paycheck. Enter the dollar amount in Step 4(a) or Step 4(b) depending on which applies to you.

Most married couples do not need to use Step 4. If you filled out Steps 1 through 3 accurately, your withholding should be close. But if you have a side business, significant investment income, or other income your employer does not know about, Step 4 lets you adjust.

You can also use Step 4(c) to claim tax credits — the child tax credit, for example. However, the IRS W-4 calculator usually handles this automatically if you entered your dependents in Step 3, so check the calculator first before manually entering credits here.

Coordinate withholding between two jobs

If both spouses work, you have two W-4 forms in play. The IRS expects the total withholding from both jobs to cover your joint tax bill. If one spouse earns much more than the other, you might put most of the withholding on the higher earner's W-4 and less on the lower earner's, or vice versa — it does not matter as long as the total is right.

The IRS W-4 calculator has a section for "multiple jobs." Use it if both of you work. It will tell you how to split the withholding between the two forms so you do not under-withhold or over-withhold.

If you change jobs, get married, or have a major life change, update your W-4 forms. You can submit a new W-4 to your employer at any time, and it takes effect on the next paycheck.

Common mistakes to avoid

Do not claim the same dependent on both spouses' W-4 forms. The IRS will catch this when you file, and you will have to amend your return. Claim each dependent once, on whichever spouse's form you choose.

Do not leave Step 2 blank if your spouse works. Your employer cannot withhold the right amount without knowing your household income. If you are unsure of your spouse's income, estimate it — you can adjust the W-4 later if the actual amount is different.

Do not assume that "married filing jointly" means you both fill out the same form or that one form covers both of you. Each spouse fills out their own W-4 at their own job. The forms are separate; the filing status just tells each employer how to calculate withholding.

Frequently Asked Questions

Do we both have to fill out a W-4, or just one of us?

If only one spouse works, only that spouse fills out a W-4. If both work, each fills out a W-4 at their own job. The forms are separate documents submitted to separate employers, but they work together to cover your joint tax bill.

What if we do not know our spouse's exact income yet?

Estimate it based on last year or your best guess. You can update your W-4 later if the actual income is different. It is better to estimate and adjust than to leave it blank, which often leads to under-withholding.

Can we claim all our dependents on one spouse's W-4?

Yes. You can claim all dependents on one spouse's W-4 and zero on the other's, or split them however you want. The key is that the total across both forms should equal your actual number of dependents. Do not claim the same child on both forms.

Do we need to use the IRS calculator, or can we just guess?

The calculator is free and takes about 10 minutes. It is more accurate than guessing, especially if you have two incomes, dependents, or other deductions. You can find it at irs.gov under "W-4 calculator."

What if we want to change our W-4 after we submit it?

You can submit a new W-4 to your employer at any time. There is no penalty for changing it. Your new withholding takes effect on the next paycheck. This is useful if your income changes, you have a baby, or your spouse's job situation changes.