W-4 withholding check: will you get a refund or owe tax for 2026?

Will I get a refund or owe tax, and which W-4 line changes it?

Check your 2026 withholding against your 2026 tax

Enter a recent pay stub and the entries on your Form W-4. The lab projects the federal tax withheld by December, compares it with the tax on your pay, and shows which W-4 line moves the gap. The values shown are samples.

Your pay stub

How often you are paid

Gross pay per paycheck*

Pre-tax deductions per paycheck

Traditional 401(k) and health premiums. They lower the wages the table sees.

Paychecks received so far in 2026*

Federal income tax withheld so far in 2026*

The year-to-date federal income tax line on your latest stub.

Your W-4

Filing status, step 1

Step 2 box is checked (two jobs, or a working spouse)

Step 3: credits for children and other dependents (a year)

$2,200 per child under 17 and $500 per other dependent on the 2026 form.

Step 4(a): other income (a year)

Step 4(b): deductions beyond the standard deduction (a year)

Itemized deductions above the standard deduction, plus tips, overtime, car loan interest, student loan interest, and the senior deduction.

Step 4(c): extra withholding per paycheck

$423

balance due is likely for 2026: $5,197 withheld by December against $5,620 of federal tax, in this sample.

This week: find Step 4 on your Form W-4 and note the extra amount per paycheck.

Tax against withholding, 2026

Federal tax on your pay$5,620
Projected withholding$5,197

Which line changes it

Step 4(c): enter $70.52 extra per paycheck, $70.52 more than now.

Taxable income: $48,900
Federal tax after step 3 credits: $5,620
Withheld per paycheck from now on: $216.15
Paychecks left in 2026: 6
Projected withholding for 2026: $5,197
Likely balance due: $423

Educational estimate for tax year 2026. Withholding per paycheck follows the Annual Percentage Method in IRS Publication 15-T (2026), Worksheet 1A. Tax uses the 2026 brackets and standard deduction. What it simplifies: pay stays the same for the rest of the year, Step 4(b) is treated as deductions beyond the standard deduction, Step 3 is the whole credit amount, and a second job is one flat annual wage. Not modeled: self-employment tax, Additional Medicare tax, other credits, and state tax. Publication 15-T (2026) · Form W-4 (2026) · Rev. Proc. 2025-32 · IRS withholding estimator

How this calculator works

Your employer withholds federal income tax from each paycheck using the IRS percentage method in Publication 15-T for 2026. The lab runs that worksheet on your numbers: gross pay for the year, minus the Step 4(b) deductions and a standard amount ($8,600, or $12,900 if married filing jointly) when the Step 2 box is unchecked, then the rate schedule for your filing status, then minus the Step 3 credits spread over the pay periods, plus any Step 4(c) extra.
The tax on your return is figured separately: pay minus pre-tax deductions, plus other income, minus the 2026 standard deduction and any Step 4(b) deductions, taxed with the 2026 brackets, minus Step 3 credits.
The lab adds the tax already withheld this year to what the table will withhold on the paychecks still to come. The difference between that projection and the tax is the likely refund or balance due.
If you owe, the fix is an extra amount on Step 4(c): the gap divided by the paychecks left. If you are due a refund and have a Step 4(c) amount, it shows how far to lower it. If you have no extra to lower, it shows how much one paycheck falls for each $1,000 of deductions you really expect on Step 4(b).

Paid every two weeks, $2,500 a paycheck, 20 paychecks in

Gross pay is $2,500 times 26, or $65,000. The table subtracts $8,600, leaving $56,400, and withholds $1,240 plus 12% of the $36,500 over $19,900, which is $5,620 a year or $216.15 a paycheck. The tax on the return is the same $5,620: $65,000 less the $16,100 standard deduction is $48,900, taxed at 10% on the first $12,400 and 12% on the rest. With $3,900 withheld after 20 paychecks and 6 left at $216.15, projected withholding is $5,196.90. The gap is $423.10, a balance due. Spread over 6 paychecks that is $70.52 more on Step 4(c).

What this assumes

The lab covers tax year 2026 only. Tables and limits change each year.
Pay stays the same for the rest of the year. Bonuses, raises, and overtime change the answer.
Step 4(b) is treated as deductions beyond the standard deduction, which is what the Deductions Worksheet on the form produces.
A second job or a working spouse is one flat annual wage. For two jobs, the IRS Tax Withholding Estimator is more exact.
Self-employment tax, Additional Medicare tax, credits other than Step 3, and state tax are not modeled.
A paycheck's withholding is rounded to the cent, as a payroll system would.

Finance Quest is educational. It is not financial advice, and no calculator here knows your full situation.

The mistake: checking withholding in December

Withholding that is short by $423 can be fixed with $70.52 on each of 6 remaining paychecks. Waiting until the last paycheck means the whole gap lands on one check, and once the year ends a new Form W-4 cannot change 2026 at all. The same is true of a refund: the money sat with the IRS all year.

Common questions

Is a refund good news?

A refund means more tax was withheld than the return needed, so the difference was an interest-free loan to the government. A balance due means too little was withheld. Neither is a penalty on its own. The lab shows the size of the gap so the choice is yours.

Which W-4 line changes my withholding?

Step 4(c) adds a flat amount to every paycheck and is the simplest way to cover a balance. Step 3 lowers withholding by the credits for children and other dependents. Step 4(b) lowers it by deductions beyond the standard deduction. Step 2 raises it for a second job.

When can I owe an underpayment penalty?

Form 1040-ES says to pay estimated tax if you expect to owe at least $1,000 after withholding and credits. The lab marks a balance of $1,000 or more as a penalty risk. The safe harbor rules, 90% of this year's tax or 100% of last year's, decide the actual penalty.

Do the new tips, overtime, and car loan interest deductions count?

The 2026 Form W-4 lets you include them in the Step 4(b) Deductions Worksheet. Enter that total on the Step 4(b) line of this lab. The lab does not check whether you qualify.

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