Federal income tax
Federal withholding is often the first layer people think about, but they still underestimate it because they assume one flat tax rate. In reality, federal income tax uses brackets and depends on filing status and your deduction setup.
FICA
Social Security and Medicare are separate from federal income tax. Even in a no-tax state, these payroll taxes still come out of your wages. That alone can make a paycheck feel much smaller than the headline salary.
State and local taxes
If you live or work in a state or city with income tax, that is another layer on top. Some locations are simple. Others have multiple brackets or local taxes that increase the drag on take-home pay.
Benefits and retirement deductions
Health insurance, dental, vision, HSA, commuter benefits, and 401(k) contributions often come out through payroll. Some of these help you by reducing taxable income, but they still reduce what lands in your bank account each pay period.
Why calculators help
A good take-home calculator turns a vague feeling into a specific breakdown. Once you can see federal tax, FICA, state tax, and pre-tax deductions separately, the paycheck usually stops feeling random.