Learn How Taxes Are Calculated From Your Paycheck

Understanding Gross Pay and Net Pay

When you receive a paycheck, the amount you actually take home is almost never the amount your employer agreed to pay you. This difference between what you earn and what you receive is one of the most important concepts in understanding payroll taxes. Your gross pay is the total amount of money your employer pays you before any deductions. Your net pay—sometimes called "take-home pay"—is what remains after taxes and other required deductions are removed.

For example, suppose you work at a retail store and your hourly wage is $16 per hour. You work 40 hours in a week, so your gross pay would be $640 before anything is subtracted. However, when you look at your actual paycheck, you might see only $520 or $550. The difference represents federal income tax, Social Security tax, Medicare tax, and possibly state and local taxes, depending on where you live.

The amount deducted from your paycheck depends on several factors: your gross income, your filing status (single, married filing jointly, head of household, etc.), the number of dependents you claim, and your state and local tax obligations. Two people earning the same gross pay may have different net pay amounts because their personal tax situations differ.

Your employer is legally required to withhold taxes from your paycheck and send that money to the government on your behalf. This system, called "pay-as-you-go" withholding, means taxes are collected throughout the year rather than in one lump sum at tax time. Understanding this distinction helps explain why your paycheck stub shows multiple line items and why the final amount is lower than expected.

Practical Takeaway: Review your most recent paycheck stub and identify your gross pay at the top. Look at all the deductions listed below it. The gross pay minus all deductions equals your net pay. Keeping a copy of several pay stubs throughout the year helps you understand your total earnings and tax withholding patterns.

Federal Income Tax Withholding Explained

Federal income tax withholding is the largest deduction for most workers. This is the money your employer sends to the U.S. Internal Revenue Service (IRS) based on estimates of what you'll owe in taxes for the year. The amount withheld is calculated using a formula that considers your gross pay, how frequently you're paid, and information you provided on Form W-4.

The W-4 form is completed when you start a new job or whenever your life circumstances change significantly. On this form, you indicate your filing status and the number of dependents you have. You can also claim additional withholdings if you want more money taken out, or you can claim allowances that reduce withholding. For example, if you're married, you might adjust your W-4 differently than a single person earning the same salary, because married couples filing jointly typically have different tax obligations.

The IRS publishes tax tables and worksheets that employers use to calculate the correct withholding amount for each paycheck. The calculation takes your gross pay for that period and applies a tax rate based on your filing status and allowances. If you're paid weekly, the employer divides your annual salary by 52 and withholds based on that weekly amount. If you're paid biweekly (every two weeks), the calculation uses a different table that accounts for 26 pay periods per year.

Federal income tax withholding is progressive, meaning higher earners pay a larger percentage of their income in taxes. For the 2024 tax year, federal income tax rates range from 10% for the lowest earners to 37% for the highest earners, but most people fall in the 12% or 22% brackets. However, the withholding from each individual paycheck is not simply a flat percentage of your gross pay—the calculation is more complex and accounts for the progressive nature of the tax system to spread withholding evenly throughout the year.

Practical Takeaway: Review your W-4 form at least once per year. If you consistently receive a large refund, you might adjust your W-4 to have less withheld so you take home more money during the year. If you owe taxes at the end of the year, you might increase your withholding. You can find the W-4 form on the IRS website and discuss changes with your human resources department.

Social Security and Medicare Taxes (FICA)

Beyond federal income tax, you'll see two other mandatory payroll deductions: Social Security tax and Medicare tax. Together, these are called FICA taxes, which stands for Federal Insurance Contributions Act. These taxes fund two important government programs: Social Security provides retirement, disability, and survivor benefits; Medicare provides health insurance for people age 65 and older and some younger people with disabilities.

Social Security tax is withheld at a flat rate of 6.2% of your gross pay, up to a certain income limit. For 2024, the Social Security wage base limit is $168,600, meaning that once your gross pay reaches that amount in a single year, no additional Social Security tax is withheld from subsequent paychecks for that year. This is why high-income earners see Social Security tax disappear from their paychecks partway through the year. Your employer also contributes an equal 6.2% on your behalf, though this doesn't appear as a deduction on your paycheck.

Medicare tax works differently. It is withheld at a flat rate of 1.45% of your gross pay with no income limit—regardless of how much you earn, Medicare tax is deducted from every paycheck. Like Social Security, your employer contributes an additional 1.45%. Additionally, there's a Medicare surtax of 0.9% that applies to higher earners. If your income exceeds certain thresholds ($200,000 for single filers, $250,000 for married filing jointly, $125,000 for married filing separately), the additional 0.9% Medicare tax is withheld from your paycheck.

Combined, Social Security and Medicare taxes take approximately 7.65% from your paycheck (6.2% + 1.45%), or 8.55% if you're subject to the additional Medicare tax. For someone earning $50,000 annually, FICA taxes would be approximately $3,825 per year. These taxes are separate from federal income tax and are withheld regardless of your W-4 filing status or number of dependents.

Practical Takeaway: Your paycheck stub should separately list Social Security tax (labeled as "SS Tax" or "OASDI") and Medicare tax. Calculate 7.65% of your gross pay to verify these amounts are correct. If you have multiple jobs, be aware that Social Security tax can be overwithheld across all employers, though you may receive a refund when you file your taxes.

State and Local Income Taxes

In addition to federal taxes, most workers in 41 states and the District of Columbia must pay state income tax. This tax funds state government operations including education, infrastructure, and social services. Nine states—Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming, and New Hampshire (for dividends and interest only)—do not have state income tax, which means workers in these states don't see state income tax withheld from their paychecks.

State income tax withholding works similarly to federal withholding. When you start a job, you complete a state tax withholding form (sometimes combined with the federal W-4) that indicates your filing status and dependents. Your employer then withholds state income tax based on state tax tables. State tax rates vary widely: some states have flat tax rates (like Colorado at 4.4% or Illinois at 4.95%), while others use progressive tax brackets similar to the federal system (like New York or California).

Many cities and municipalities also impose local income taxes. Cities like New York City, Philadelphia, and Columbus, Ohio collect local income tax from residents and sometimes from people who work within the city limits. Local income tax rates typically range from 1% to 3.8% of gross income. If you work in a city with local income tax but live outside that city, your employer may or may not be required to withhold local taxes—this depends on local laws and your employer's policies.

Some states have different tax rules for different types of income. For example, many states exempt retirement income or Social Security from taxation. Others tax wages at one rate and interest or capital gains at another rate.