Paycheck Tax FAQ
Answers to the most common questions about paycheck withholding, federal and state taxes, and how to maximize your take-home pay.
How is federal income tax calculated from my paycheck?
Your employer uses IRS Publication 15-T to calculate withholding. They start with your gross pay, annualize it, subtract your W-4 allowances, then apply the tax brackets for the year. The result is divided by your pay periods to determine each paycheck's federal withholding.
What is the difference between gross pay and net pay?
Gross pay is your total compensation before any taxes or deductions. Net pay (take-home pay) is what you receive after federal income tax, Social Security, Medicare, state income tax, and any voluntary deductions are subtracted.
What does FICA stand for, and what does it cover?
FICA stands for the Federal Insurance Contributions Act. It covers Social Security (6.2% of wages up to $168,600 in 2024) and Medicare (1.45% on all wages). Your employer matches both contributions. The money funds retirement benefits (Social Security) and hospital insurance (Medicare).
What is the additional Medicare surtax?
High earners pay an extra 0.9% Medicare tax on wages above $200,000 (single) or $250,000 (married filing jointly). Unlike the base Medicare tax, employers do not match this additional 0.9%.
How do pre-tax deductions reduce my taxes?
Pre-tax deductions — including traditional 401(k) contributions, health insurance premiums (employer-sponsored plans), HSA deposits, and FSA contributions — are subtracted from your gross pay before income taxes are calculated. This lowers your taxable income and reduces both federal and state income tax withholding.
What is the 2024 standard deduction?
The 2024 standard deduction is $14,600 for single filers, $29,200 for married filing jointly, and $21,900 for head of household. This amount is subtracted from your income before tax brackets are applied, reducing your taxable income.
What is my marginal tax rate vs my effective tax rate?
Your marginal rate is the rate applied to your last dollar of income (your "top bracket"). Your effective rate is your total tax divided by total income — it is always lower than the marginal rate because lower brackets apply to earlier income. For example, a $100,000 single filer has a 22% marginal rate but roughly a 16% effective federal rate.
How do I update my W-4 to change my withholding?
Submit a new IRS Form W-4 to your employer's payroll department. You can increase withholding by adding an extra dollar amount in Step 4(c), or decrease it by claiming additional deductions in Step 4(b). The IRS W-4 estimator at IRS.gov can help you fill it out accurately.
Why do I owe taxes at the end of the year?
You may owe at filing if you were under-withheld during the year. This happens when multiple jobs push you into a higher bracket, you have side income not subject to withholding, or your W-4 was not updated after a life change (marriage, new job, etc.). Adding extra withholding in Step 4(c) of your W-4 can prevent a balance due.
What states have no income tax?
Nine states levy no income tax on wages: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. New Hampshire taxes investment income but not earned wages.
How does filing status affect my take-home pay?
Married filing jointly gets a higher standard deduction ($29,200 vs $14,600) and wider tax brackets than single filers, generally resulting in lower tax withholding per dollar of income. Head of household gets a deduction between the two ($21,900) and is available to unmarried individuals who pay more than half the cost of maintaining a home for a qualifying person.
What is a 401(k) and how does it reduce taxes?
A traditional 401(k) is an employer-sponsored retirement account funded with pre-tax dollars. Contributions are not subject to federal or state income tax in the year contributed, reducing your taxable income. The 2024 contribution limit is $23,000 ($30,500 for those 50 or older). Taxes are deferred until withdrawal in retirement.
What is the difference between a traditional and Roth 401(k)?
Traditional 401(k) contributions are made pre-tax, reducing your current taxable income. Roth 401(k) contributions are post-tax — you pay taxes on the money now, but qualified withdrawals in retirement are tax-free. This calculator shows both separately in the deductions breakdown.
What is an HSA and how much can I contribute?
A Health Savings Account (HSA) is a tax-advantaged account for medical expenses, available only with a high-deductible health plan (HDHP). Contributions are pre-tax, growth is tax-free, and withdrawals for qualified medical expenses are tax-free. 2024 limits: $4,150 (self-only) and $8,300 (family).
What is an FSA?
A Flexible Spending Account (FSA) lets you set aside pre-tax dollars for qualified medical or dependent care expenses. The 2024 healthcare FSA limit is $3,200. Unlike an HSA, most FSA balances must be used within the plan year (with a grace period or $640 rollover allowed by some plans).
How do I calculate my own paycheck taxes manually?
Annualize your gross pay, subtract pre-tax deductions and the standard deduction to get federal taxable income, apply the bracket table to find federal income tax, calculate Social Security (6.2%) and Medicare (1.45%) on gross wages, add state income tax, then divide all annual amounts by your pay periods per year.
Does overtime pay get taxed at a higher rate?
Overtime pay is taxed the same as regular wages — at your marginal bracket rate. However, because a larger paycheck is annualized for withholding purposes, your employer may withhold at a higher rate for that pay period. Your actual tax for the year is the same regardless of how income is distributed across paychecks.
Are bonuses taxed differently?
Supplemental wages like bonuses are often withheld at a flat 22% federal rate (up to $1 million). However, your actual tax liability is the same as if the bonus were regular wages — you reconcile any over- or under-withholding when you file your annual return.
What if I work in a different state than I live in?
Many states have reciprocity agreements where you only pay taxes in your home state. If no agreement exists, you may owe taxes in both states, though most states offer a credit for taxes paid to another state to prevent full double taxation. This calculator handles single-state scenarios.
How accurate is this calculator?
This calculator uses 2024 IRS brackets and published state tax rates to produce accurate estimates for standard W-2 employment. It does not account for tax credits, AMT, local city taxes, itemized deductions, or self-employment. For complex situations — multiple income sources, significant investment income, or business income — consult a CPA or enrolled agent.
What are Social Security and Medicare wage bases in 2024?
In 2024, Social Security tax applies to the first $168,600 of wages (the "wage base"). Medicare applies to all wages with no cap. An additional 0.9% Medicare surtax applies to wages above $200,000 (single) or $250,000 (married filing jointly).
Can I use this calculator for self-employment income?
This calculator is designed for W-2 employees. Self-employed individuals pay the full 15.3% self-employment tax (both employee and employer share of FICA) and may use Schedule C deductions. A different calculator specifically for self-employment income would be more appropriate.
Ready to calculate your take-home pay? Use our free paycheck calculator for all 50 US states with 2024 tax brackets.