W-4 Calculator 2026

How this W-4 calculator works

Your employer does not guess at your withholding. It runs your Form W-4 through the formula in IRS Publication 15-T: annualize your pay, add Step 4(a), subtract Step 4(b) and a built-in allowance of $8,600 ($12,900 if married filing jointly) unless the Step 2 box is checked, look up the tax in a rate table, subtract Step 3 and add Step 4(c). This calculator runs the same formula, then compares the result with an estimate of the federal income tax you will actually owe for 2026.

The tax estimate uses the 2026 brackets and standard deduction, the child tax credit with its income phase-out, and the new deductions for tips, overtime, car loan interest and seniors with their Schedule 1-A limits. The gap between the two is what Step 4(c) closes, rounded up to a whole dollar per paycheck.

Example W-4 entries

Paid every two weeks, federal income tax only. Two-earner couples are the classic case of under-withholding: each blank W-4 assumes that job is the household's only income.

What changed on the 2026 Form W-4

• Step 3 uses $2,200 per qualifying child under 17 and $500 per other dependent.
• The Step 4(b) Deductions Worksheet adds lines for qualified tips, the "and-a-half" part of overtime, car loan interest, and $6,000 for each person 65 or older, each with an income limit.
• People who take the standard deduction can include cash gifts to charity, up to $1,000 ($2,000 joint).
• The standard deduction on the worksheet is $16,100 single, $24,150 head of household and $32,200 joint.

Two jobs or a working spouse

Step 2 gives three choices: the IRS online estimator, the Multiple Jobs Worksheet, or a checkbox you tick on both Forms W-4 when there are exactly two jobs. The IRS notes the checkbox is generally more accurate when the lower-paying job pays more than half as much as the higher one. This calculator follows that rule: it checks the box for similar jobs, and otherwise leaves it unchecked and puts the exact shortfall in Step 4(c) on the higher-paying job. Complete Steps 3 and 4(b) on only one W-4, ideally the higher-paying job's.

Common W-4 mistakes that lead to a tax bill

• Two earners, two blank forms. Each employer withholds as if its job were the only income, so the second paycheck gets the full standard deduction and low brackets again. The examples above show how quickly that adds up.
• Checking the Step 2 box on only one form. The box halves the standard deduction and brackets, so it has to be checked on both jobs' Forms W-4 to work.
• Claiming dependents on both forms. Steps 3 through 4(b) belong on one Form W-4 only. Entering the child credit on two forms doubles it in your withholding.
• Using the checkbox when pay is very different. It is accurate for similar pay; with one large and one small job it over-withholds, and the refund you did not need grows with the gap.
• Never updating the form. A raise, a new baby, marriage, a second job, or new deductions such as tips or overtime all change the right entries. The IRS suggests rechecking at the start of each year.

Sources and limitations

Withholding follows IRS Publication 15-T (2026), Worksheet 1A and the 2026 Form W-4. The estimate assumes the same pay all year, treats credits as reducing tax to no less than zero (it leaves out the refundable part of the child tax credit), and does not cover self-employment tax, state withholding or credits other than the child and dependent credits. If you start a job mid-year, the IRS estimator can use your year-to-date pay.

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