Form W-4 explained: how it decides your withholding

The W-4 is the form your employer uses to decide how much federal income tax to hold back from each check. It does not change what you owe for the year. It changes how much of that you pay through payroll versus at filing time.

Step 1 sets the baseline

Your filing status picks the withholding table. Single and married filing jointly use different bracket widths and different standard deductions, $16,100 against $32,200 this year, so this one box moves the number more than any other.

Step 2 is for two jobs or two earners

Withholding tables assume each job is your only income. Two jobs each withhold as if you have two standard deductions, and you only get one. Checking the box in Step 2 tells payroll to withhold at the higher single-job rate, which is usually right for two similar salaries. The worksheet or the IRS estimator is better when the two incomes differ a lot.

Step 3 reduces withholding for dependants

You enter the child tax credit and other dependant credits as a dollar amount. Payroll spreads that across the year and holds back less. Enter it on one job only if you have two.

Step 4 is the manual override

Other income adds withholding for money that has none of its own, such as interest or a side business. Deductions lets you claim more than the standard deduction if you itemise. Extra withholding is a flat dollar amount per check, which is the simplest way to fix a return that keeps coming out with a balance due.

Why there are no allowances

The 2020 redesign removed them. Allowances were a multiple of the personal exemption, which the 2017 tax law set to zero, so the concept stopped meaning anything. If someone tells you to claim zero or one, they are describing the old form.

How to check it is right

Take your last stub's year-to-date federal withholding, project it to December, and compare it with what a calculator says you owe on the year. On $60,000 single that liability is $5,020. A gap of a few hundred dollars either way is normal; a gap of thousands means the form needs a change.

Run your own numbers

Every figure above came from the paycheck calculator with 2026 rates.

Frequently asked questions

Can I change my W-4 during the year?

Yes, whenever you like. Employers must apply a new one by the start of the first payroll period ending 30 days or more after they receive it. People commonly update it after a marriage, a child, a second job or a large refund.

Is it better to owe or to get a refund?

A refund is your own money returned without interest. Owing a small amount means you kept the money all year. The IRS only charges an underpayment penalty if you withheld less than 90% of this year's tax or 100% of last year's, so a small balance due is not a problem.

Does the W-4 affect Social Security and Medicare?

No. Those are flat percentages of wages and nothing on the form changes them. The W-4 only controls federal income tax withholding, and a separate state form controls state withholding where there is one.