W-4 Withholding Calculator
Your Form W-4 is the only direct control you have over federal withholding, and every entry on it does something specific and predictable. Change the fields below to see what a new W-4 would do to your paycheck before you hand one to payroll.
Tax year 2026 · Updated 2026-08-29 · Federal, state and local withholding · Free, no sign-up
Loading calculator…
Enable JavaScript to use the calculator. The tax tables and worked examples on this page stay readable without it.
What each W-4 step actually does
Step 1(c), filing status. Selects which withholding schedule applies. Head of household withholds less than single at the same income.
Step 2(c), the checkbox. The single most consequential box on the form. Ticking it switches you to a schedule with half-width brackets and removes the standard-deduction offset entirely, which is roughly correct when a household has two similar incomes. Leaving it blank when you have a second job is the most common cause of an April balance due.
Step 3, dependent credits. An annual dollar amount — $2,200 per qualifying child under 17 and $500 per other dependent for 2026 — divided across your pay periods and subtracted from the computed tax. It can reduce withholding to zero but never below it.
Step 4(a), other income. Added to your annualized wages before the tables are applied. Use it for interest, dividends or a side income with no withholding of its own.
Step 4(b), deductions. Subtracted from annualized wages. This is where the 2026 tips, overtime and senior deductions go, and where itemised deductions above the standard amount go.
Step 4(c), extra withholding. A flat dollar amount added per paycheck, after everything else. It is the bluntest and most reliable tool for closing a known shortfall.
When to file a new W-4
Any time your household's tax picture changes materially: marriage or divorce, a birth or adoption, a spouse starting or leaving work, a second job beginning or ending, a large raise, or the year you turn 65. Also file one in January if last year produced a refund or a balance you were unhappy with.
You do not need a reason and there is no limit on how often you can submit one. Employers must put a new W-4 into effect no later than the start of the first payroll period ending on or after the thirtieth day from the date you give it to them.
Fixing an under-withholding problem mid-year
If you discover in July that you are short, dividing the shortfall by the number of remaining pay periods and entering that on Step 4(c) is the cleanest fix — it is exact, it is easy to reverse in January, and it does not distort anything else.
The alternative, reducing dependent credits on Step 3, is less precise and can look like you are claiming fewer children than you have. Use Step 4(c).
Frequently asked questions
How do I fill out a W-4 to have more tax withheld?
Enter an extra dollar amount per paycheck on Step 4(c). That is the direct control. Checking the Step 2(c) box also increases withholding substantially, but only do that if you genuinely have two jobs or a working spouse.
Should I claim 0 or 1 on my W-4?
Neither — allowances were removed from the W-4 in 2020. The modern form asks for filing status, dependent credit dollars and adjustments instead. If someone tells you to claim zero, what they mean is to withhold at the highest rate, which today is the Step 2(c) checkbox plus extra on Step 4(c).
What happens if I fill out my W-4 wrong?
Nothing is filed with the IRS, so there is no penalty for the form itself. The consequence is simply that too much or too little is withheld, and you settle up when you file. If too little is withheld you can owe an underpayment penalty, which is avoided by paying at least 90% of the current year's tax or 100% of last year's — 110% for higher incomes.
Do I need to file a new W-4 every year?
No, an existing W-4 stays in effect indefinitely. The exception is if you claimed exempt status, which must be renewed by 15 February each year.