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How Does Salary Tax Withholding Work on a Paycheck?

Published Updated Tax Muhammad Rashid

Tax withholding is the income tax your employer takes out of each paycheck and sends to the IRS on your behalf, based on the Form W-4 you filed and the IRS withholding tables in Publication 15-T. Your employer also withholds Social Security at 6.2% and Medicare at 1.45% of wages. At tax time, the federal income tax withheld during the year is credited against what you actually owe, so you get a refund if too much was taken or owe a balance if too little was.

This guide explains each piece of the process, walks through a 2026 example, and shows how to adjust it.

How does the W-4 control what is withheld?

Form W-4 tells your employer how to figure your federal income tax withholding. The current form no longer uses allowances. Instead it asks for:

  • Step 1: your filing status
  • Step 2: whether you have more than one job or your spouse works
  • Step 3: credits for children and other dependents
  • Step 4: other income, extra deductions and any extra amount to withhold
  • Step 5: your signature

If you do not give your employer a W-4, the IRS rules require them to withhold as if you were single with no adjustments. That often means more taken out than a married worker with children would need.

How does the employer calculate it?

Employers follow IRS Publication 15-T, which has wage bracket tables and a percentage method. In simple terms, the employer annualizes your pay, applies the standard deduction built into the tables for your filing status, runs the result through the tax brackets, subtracts any credits from Step 3, and divides back to a per-paycheck amount.

What does a worked 2026 example look like?

Take a single filer earning $60,000 a year, paid monthly at $5,000, with no other adjustments. The IRS 2026 inflation adjustments set the standard deduction for single filers at $16,100, with a 10% bracket up to $12,400 and 12% from $12,401 to $50,400.

  • Annual wages: $60,000
  • Less standard deduction: $60,000 − $16,100 = $43,900 taxable
  • 10% on the first $12,400: $1,240
  • 12% on the remaining $31,500: $3,780
  • Estimated annual income tax: $5,020
  • Per monthly paycheck: $5,020 ÷ 12 ≈ $418

The exact amount from Publication 15-T may differ by a few dollars because of rounding in the tables, but it lands close to this. On top of that:

  • Social Security: $5,000 × 6.2% = $310
  • Medicare: $5,000 × 1.45% = $72.50

Take-home before state tax and benefits is about $5,000 − $418 − $310 − $72.50 = $4,199.50. You can check your own numbers with the salary tax calculator.

What does FICA add?

FICA covers Social Security and Medicare. The IRS says employees pay 6.2% for Social Security, up to the annual wage base, and 1.45% for Medicare on all wages. An additional 0.9% Medicare tax applies to wages above $200,000 in a calendar year, and employers must start withholding it once your pay from them passes that amount. Unlike income tax withholding, FICA does not depend on your W-4.

Why are bonuses withheld differently?

Bonuses and commissions are supplemental wages. Publication 15-T and the employer guides allow employers to withhold federal income tax on them at a flat rate when paid separately from regular wages, instead of running them through the normal tables. The flat rate is often higher or lower than your actual bracket, which is why a bonus check can look over-taxed or under-taxed. The difference is settled when you file your return.

How do I know if my tax withholding is right?

Signs it may be off:

  • You had a large refund last year, meaning you overpaid all year
  • You owed a balance, or an underpayment penalty
  • You started a second job, or your spouse started working
  • You had a baby, married, divorced or bought a home
  • You have significant income with no withholding, such as freelance or investment income

IRS Publication 505 covers tax withholding and estimated tax in detail, including how to avoid the penalty for paying too little during the year. Use the IRS Tax Withholding Estimator or your latest pay stub to compare year-to-date withholding with your projected tax. The income tax calculator gives a full-year estimate to compare against.

How do I change my tax withholding?

Give your employer a new W-4 at any time. To withhold more, enter an extra amount per paycheck in Step 4(c). To withhold less, claim dependents in Step 3 or extra deductions in Step 4(b). If you have two jobs, fill out Step 2 on only one W-4, or the jobs will each assume they are your only income and under-withhold.

If you have income that is not subject to tax withholding, such as self-employment profit, you can either raise your paycheck withholding or make quarterly payments. The quarterly estimated tax calculator shows what each payment would need to be.

Does overtime change what is withheld?

Overtime is regular wages, so it is withheld through the same tables, which can push a single paycheck into a higher withholding amount. Under recent law, some workers can deduct part of qualified overtime pay on their return; see the overtime tax calculator for how that works at filing time.

Tax withholding is a prepayment, not the final bill. Getting your W-4 right means a smaller surprise in April and more of your money in your paycheck during the year. Compare monthly take-home under different raises with the percentage calculator.

Sources

FAQ

What does “How Does Salary Tax Withholding Work on a Paycheck?” explain?

Tax withholding is the income tax your employer takes out of each paycheck and sends to the IRS on your behalf, based on the Form W-4 you filed and the IRS withholding tables in Publication 15-T. Your employer also with…

How should I use this guide with a calculator?

Read the definitions and assumptions first, then open the linked calculator with the same inputs. Treat results as estimates, not professional advice.

Is this financial or medical advice?

No. Calcenzo content is educational. Confirm important decisions with a qualified professional and official sources for your situation.

Open the Salary Tax Calculator

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