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IRS Publication 15-T · tax year 2026 · engine 2026.2.1

W-4 withholding calculator: refund or bill?

Your employer withholds one amount every payday. Your return settles a different one at the end of the year. This calculator runs both on the same wages — the Publication 15-T percentage method per check, and the estimated federal income tax for the year — and shows the gap between them, which is the refund or the bill.

Your pay, then your W-4

Four steps, in the order the form asks · inputs stay in your browser

Pay details

Traditional deferrals lower the wages withholding is figured on.

Health and dental premiums, HSA — they lower the same wage base.

  1. 1
  2. 2
  3. 3
  4. 4
Step 1 — who you are

Filing status picks which Publication 15-T table your employer reads.

Married filing separately uses the same table as single, so this page treats the two together.

Withheld per check after this step $218.65 26 checks a year · standard schedule W-4 line 1(c)

Step 2 — more than one job

Checking the box moves you to the higher withholding schedule, because one job alone cannot see the household total.

Leave it off if this is the only job in the household.

Withheld per check after this step $218.65 $0.00 versus the previous step W-4 line 2(c)

Step 3 — dependants and credits

The annual credit total you entered on the form is spread evenly across your checks.

Copy the dollar total you wrote on line 3 — this page never decides what you may claim.

Withheld per check after this step $218.65 $0.00 versus the previous step W-4 line 3

Step 4 — other adjustments

Other income raises withholding, deductions lower it, and 4(c) adds a flat amount to every check.

Exempt means no federal income tax is withheld; the eligibility conditions are printed on the form.

Withheld per check after this step $243.65 +$25.00 versus the previous step W-4 lines 4(a), 4(b), 4(c)

Annual tax liability is estimated and spread evenly across pay periods; employer withholding tables can differ. Nothing you type leaves your browser.

Two engines, two questions

1. What the employer withholds

Publication 15-T Worksheet 1A annualises the taxable wages in one pay period, adjusts them for your Form W-4 Step 4 entries, reads a tentative annual amount from the 2026 percentage-method table for your Step 1(c) status and Step 2 checkbox, divides by the number of pay periods, subtracts the Step 3 credit per period and adds the Step 4(c) extra. The audit trail in the result panel prints those lines.

2. What the year actually costs

The liability estimate takes the same wages for the whole year, subtracts the 2026 standard deduction for your filing status and runs them through the federal brackets. It is the same engine behind every other calculator on this site.

3. The gap is the refund or the bill

Annualised withholding minus estimated liability. Positive means more was withheld than the estimate says is owed — a refund. Negative means less — a payment. A gap inside a dollar over a whole year is shown as “about even”, because a year of per-period cent rounding never lands on a perfect zero.

Withholding is not figured on gross pay

Both sides use federal income-taxable wages: gross pay minus the traditional 401(k) deferral and the §125 pre-tax deductions. The page reads that base back from the take-home engine instead of recomputing it, so the two figures can never drift apart.

Important limits

  • Federal income tax only. Social Security, Medicare and state income tax are withheld under their own rules and are not part of this comparison.
  • One job, one W-4. Income from a second job, a spouse, self-employment or investments changes the liability side in ways this page cannot see.
  • The liability estimate uses the standard deduction and models no tax credits, so Step 3 and Step 4 entries that describe credits, other income or itemised deductions will widen the gap shown here.
  • Employers may use other Publication 15-T methods and the optional whole-dollar rounding convention; bonuses and other supplemental wages follow separate rules.
  • Results are estimates for planning — not tax, legal or financial advice, and not a recommendation about what to put on your W-4.

Frequently asked questions

Why does my refund or bill exist at all?

Your employer does not know your tax return. Each payday it runs the Publication 15-T percentage method on that one check, using only the entries on your Form W-4. Your return computes the tax on the whole year. The two answers rarely match to the dollar, and the difference is settled in April — as a refund when more was withheld than owed, or as a payment when less was.

What does this calculator compare, exactly?

Federal income tax only, on the wages from this one job. The left figure is the Publication 15-T amount per pay period, multiplied by the number of periods in the year. The right figure is the estimated annual federal income tax on the same wages using the standard deduction. Social Security, Medicare and state income tax are withheld separately and are not part of this comparison.

Is withholding calculated on my gross pay?

No. It is calculated on federal income-taxable wages for the period: gross pay minus pre-tax amounts such as a traditional 401(k) deferral and §125 health premiums. That is why raising your 401(k) percentage lowers the tax withheld from every check even though your gross pay has not changed.

Should I change my W-4?

That is your decision, and this page will not make it for you. What it does is show what the arithmetic produces for the entries you type — nothing here is tax, legal or financial advice. If you want an official figure before filing a new form, the IRS Tax Withholding Estimator is the government tool for that, and your employer’s payroll team applies whatever you submit.

Why did entering a Step 3 credit turn my refund into a bill?

Step 3 credits reduce what is withheld from each paycheck immediately. The liability side of this page estimates tax before credits, so the credit shows up as a shortfall. If you will actually claim those credits on your return, the real settlement is closer than the number here suggests. The same caution applies to Step 4(a) and 4(b), which describe income and deductions this page cannot see.

What does the exempt certification do?

An employee who certifies exemption below Step 4(c) has no federal income tax withheld at all. The estimated liability does not disappear with it, so the calculator shows the entire year’s estimated tax as an amount owed. Exemption has strict eligibility conditions set out in the Form W-4 instructions.

Does this match my pay stub to the cent?

No, and it is not meant to. These are 2026 planning estimates. Employers may use other Publication 15-T methods, may apply the optional whole-dollar rounding convention, and handle bonuses and mid-year changes their own way. Local taxes, credits and itemised deductions are not modelled here.

Official sources

Engine 2026.2.1, tax year 2026, reviewed September 5, 2026. The parameter set, the changelog and the known limitations are published on the methodology page. Estimates only — not tax, legal or financial advice.