What the form actually controls, each of its five steps in plain language, and how to tell whether your withholding is set too high or too low, using the 2026 form.
| Step | What it asks | Who fills it in |
|---|---|---|
| 1 | Name, address, Social Security number, filing status | Everyone |
| 2 | Multiple jobs, or a spouse who works | Only if it applies |
| 3 | Children and other dependents | Income of $200,000 or less ($400,000 jointly) |
| 4 | Other income, deductions, extra withholding | Only if it applies |
| 5 | Signature and date | Everyone |
Step 3 is where most people with children change their withholding. For 2026 it counts $2,200 for each child under 17 and $500 for each other dependent, and it applies if your income is $200,000 or less, or $400,000 or less for a married couple filing jointly. On a paycheck every two weeks, one child means $84.62 less federal tax withheld from each check.
Step 4 has three lines: other income with no tax withheld, such as interest or a side job; deductions beyond the standard deduction; and any extra amount you want withheld each pay period. The 2026 form also adds room on its deductions worksheet for the new deductions for qualified tips and overtime pay.
Withholding is an estimate, and a refund means too much was taken out during the year. A $2,400 refund on biweekly pay is $92.31 from every check that you could have had, and saved, all along. Owing a large amount in April is the opposite problem: too little was withheld.
The fix for either is a new W-4 with your employer, which you can hand in at any time. A second job, a new baby, a raise, a spouse starting work or a side business are all good reasons to check. The paycheck calculator shows what each check looks like before and after.
You can claim exemption from withholding only if you owed no federal income tax last year and expect to owe none this year. On the 2026 form it is a checkbox below Step 4. An exemption lasts for one year, so it has to be claimed again on a new form early the next year or full withholding starts again.
Amounts are from the IRS's 2026 Form W-4. The per-check figures divide the yearly amount by 26 biweekly paychecks; employers use the IRS's own withholding tables, so a real paycheck can differ slightly.
Nothing is saved or sent anywhere; this just checks your answers in the page itself.