How Federal Income Tax Is Calculated on Your Paycheck

Every US employer withholds federal income tax from employee wages using a method published by the IRS in IRS Publication 15-T, Federal Income Tax Withholding Methods. The calculator on this site encodes the same 2026 tables to produce employer-consistent estimates.

The percentage method: step by step

Employers are required to use a withholding method approved by the IRS. The most common is the percentage method, which works as follows:

1. Determine the adjusted annual wage. The employer annualizes gross wages for the pay period (multiply biweekly wages by 26), then subtracts the standard withholding allowance from Publication 15-T based on the employee's W-4 filing status.
2. Apply the graduated withholding table. The adjusted annual wage falls into a bracket tier from Publication 15-T. The applicable rate applies only to the income within that tier — not to all wages.
3. Convert back to the pay period. The annual withholding amount is divided by 26 (for biweekly) to produce the per-paycheck withholding figure.
4. Apply any additional W-4 elections. Step 3 (dependent credits) reduces withholding; Step 4c (additional withholding) increases it.

Example: $75,000 salary, single filer, biweekly

Tax	Annual	Per biweekly paycheck
Gross pay	$75,000	$2,884.62
Federal income tax	−$7,670	−$295
Social Security	−$4,650	−$179
Medicare	−$1,088	−$42
Texas state tax (none)	$0	$0
Estimated net take-home	≈ $61,593	≈ $2,369

Federal withholding shown is $7,670 per year / $295.00 per biweekly paycheck, using IRS Pub 15-T 2026 percentage-method tables.

Example: $100,000 salary, single filer, biweekly

Tax	Annual	Per biweekly paycheck
Gross pay	$100,000	$3,846.15
Federal income tax	−$13,170	−$507
Social Security	−$6,200	−$238
Medicare	−$1,450	−$56
Texas state tax (none)	$0	$0
Estimated net take-home	≈ $79,180	≈ $3,045

What the W-4 changes

The 2020-redesigned Form W-4 removed personal allowances. Key election points are: Step 2 (multiple jobs), Step 3 (dependent credits that reduce withholding), and Step 4c (extra withholding added each period). A newly hired employee who completes only Step 1 (personal info) with a single or married filing status gets the default withholding calculation from the IRS tables.

Federal withholding vs actual tax liability

Withholding is a pay-period estimate — it is not the same as the tax you owe. Over or under-withholding is reconciled when you file your annual return. If you owe at filing, adjusting your W-4 during the year can help. If you received a large refund, you may have over-withheld and can increase take-home by updating Step 4c.

Withholding vs annual tax liability

Your employer withholds federal income tax from each paycheck using IRS Publication 15-T tables. Withholding is a running estimate of annual liability based on current wages, filing status, and W-4 entries. Your Form 1040 reconciles the full year — which may produce a refund or balance due.

Taxable wages start after pre-tax deductions

401(k), HSA, health insurance, and other pre-tax benefits reduce wages subject to federal withholding. Post-tax deductions do not reduce federal income tax withholding. Enter your elections in the paycheck calculator to model taxable wages accurately.

Filing status changes the curve

Single, married filing jointly, and head of household each use different withholding tables. A married worker may see lower per-check federal withholding than a single filer at the same gross salary if W-4 entries reflect a two-earner household correctly.

Pay frequency annualization

Payroll systems annualize current wages based on pay frequency — biweekly (26 periods), semi-monthly (24), weekly (52), or monthly (12). The same annual salary produces different per-check federal withholding when frequency changes because the annualization factor changes.

Supplemental wages and bonuses

Bonuses and some other payments may use flat-rate supplemental withholding methods that differ from regular wage tables. See bonus tax withholding for structural guidance.

Official sources

IRS Publication 15-T (Employer's Tax Guide supplement) and the current Form W-4 are primary sources. ExactTakeHome encodes federal brackets and standard deductions from official IRS data for 2026.

Related guides

Federal tax methodology, W-4 withholding guide, and W-4 withholding calculator provide additional depth.

Frequently Asked Questions

Figures and methods are based on official-source data encoded in the calculator. Not tax advice. Review the methodology and consult a qualified professional for your situation.