The W-4, step by step

Step 1 — Name, address, filing status

Step 1(c) picks the schedule: Single or married filing separately, Married filing jointly, or Head of household. The schedules differ in two ways — the standard deduction amount built into the withholding adjustment ($8,600 a year for single and head of household, $12,900 for married filing jointly) and the bracket widths. One quirk worth knowing: "single or married filing separately" is a single checkbox on the form, and Publication 15-T has one shared schedule set for it.

Step 2 — Multiple jobs or a working spouse

Do this step only if you hold more than one job at a time, or file jointly with a working spouse, and the combined pay passes the form's threshold. Checking the box in Step 2(c) — the right choice when the two jobs are similar in pay — switches your employer to the "Step 2 checkbox" schedules, which withhold at higher effective rates so the two paychecks together approximate the tax on the combined income. On the calculator, F-04-style comparisons show the size of the difference: on $3,000 biweekly single, checking the box moves federal withholding from about $320 to about $503 a check. The Step 2 adjustment also removes the standard withholding adjustment, which is the part people notice.

Step 3 — Dependents

Enter the total dollar amount, not a count. The 2026 Form W-4's own guidance: $2,200 for each qualifying child under 17 and $500 for each other dependent, summed. The full amount comes off your annual withholding before it is divided into checks — enter $4,000 of Step 3 on monthly pay and federal withholding drops by $333.33 a check, floored at zero.

Step 4 — Other adjustments (optional)

4(a) adds other annual income (interest, dividends, a side business) to your annualized wages, raising withholding. 4(b) adds deductions above the standard amount — if you itemize, the excess over the standard deduction for your status goes here, lowering withholding. 4(c) is the blunt instrument: a fixed extra dollar amount withheld from every check, added after everything else, even when the rest of the computation floors at zero.

Step 5 — Sign and date

An unsigned W-4 is not a W-4. If you never file one, your employer withholds as single with no other adjustments — the calculator's defaults until you change them.

When to file a new one

After a marriage, divorce, a child, a spouse starting or leaving work, a second job, or a refund or balance due that surprised you two years running. Withholding is a prepayment: the goal is not a big refund (an interest-free loan you made all year) or a balance due, but a stub whose federal line tracks the return you will actually file. Run your situation on the calculator before you hand payroll the new form, and keep in mind states have their own forms — each state page names the one that applies.