What Is Federal Income Tax Withholding?

“Federal withholding” is usually the single biggest line on a US paycheck — but it’s widely misunderstood. It is not your final tax bill. It’s an estimate your employer pays to the IRS on your behalf throughout the year, settled up when you file.

How it works

Each payday, your employer estimates how much federal income tax you’ll owe for the year, divides it across your paychecks, and sends that amount to the IRS. The estimate is based on the W-4 form you filled out — your filing status, dependents and any extra withholding you requested.

Withholding vs the taxes that aren’t adjustable

• Federal income tax — adjustable via your W-4 (this is “withholding”).
• Social Security & Medicare (FICA) — fixed at 7.65%, not adjustable. See FICA explained.
• State income tax — withheld separately where it applies.

Getting it right

The goal is to withhold close to what you’ll actually owe — neither a huge refund nor a surprise bill. Update your W-4 after a raise, a second job, marriage, or a new child. The IRS Tax Withholding Estimator can help, and our calculator shows your expected federal tax so you can sanity-check it.

See your numbers

Enter your salary in the calculator to see your estimated federal income tax alongside FICA and state tax — a good baseline for checking your withholding.