Question 1

How is federal income tax withheld?

Accepted Answer

Federal withholding is calculated by annualizing your gross pay, subtracting the standard deduction and allowances, applying the tax brackets, then dividing by the number of pay periods.

Question 2

What is FICA?

Accepted Answer

FICA is the Federal Insurance Contributions Act tax, covering Social Security (6.2%) and Medicare (1.45%). Your employer matches these amounts. Self-employed workers pay both sides (15.3%).

Question 3

What is the additional Medicare tax?

Accepted Answer

An extra 0.9% Medicare surtax applies to income above $200,000 for single filers ($250,000 for married filing jointly). It's only withheld from employee wages — not matched by employers.

Question 4

Why does my paycheck net differ from the calculator?

Accepted Answer

State taxes, local taxes, pre-tax benefits (health insurance, HSA, 401k), and after-tax deductions all affect take-home pay. This calculator shows federal-only withholding as a baseline.

Question 5

What is the difference between biweekly and semi-monthly?

Accepted Answer

Biweekly means every 2 weeks — 26 paychecks per year. Semi-monthly means twice per month — 24 paychecks. Biweekly results in 2 extra paychecks per year.

Question 6

How do pre-tax deductions affect my taxes?

Accepted Answer

Pre-tax deductions like 401(k) contributions and health insurance premiums reduce your taxable income. A $500/paycheck 401(k) contribution can save $110–$185 in federal taxes at common bracket rates.

Question 7

What W-4 filing status should I choose?

Accepted Answer

Use your actual tax filing status. Single or Married Filing Separately results in more withholding than Married Filing Jointly. If you have two incomes in a household, use the Multiple Jobs worksheet on W-4 Step 2.

Question 8

How is state income tax calculated?

Accepted Answer

State income tax varies widely — from 0% (Florida, Texas, WA) to over 13% (California). This calculator focuses on federal withholding; add your state rate separately for a complete picture.

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Common questions

You might also need

US Income Tax Calculator

W-4 Withholding Calculator

Take-Home Pay Calculator