The difference between payroll taxes and income taxes

Payroll taxes and income taxes are two separate deductions from your paycheck that fund different government programs. Income taxes go to the federal government (and sometimes your state) to pay for general government operations. Payroll taxes—Social Security and Medicare—are withheld specifically to fund those two programs, and the rate is fixed by law regardless of how much you earn.

The key difference is what they fund and how they work. When you see your pay stub, income tax withholding is calculated based on your total income and the W-4 form you filled out with your employer. Payroll taxes are a flat percentage: 6.2% for Social Security and 1.45% for Medicare, taken from every dollar you earn up to a certain limit (Social Security stops at $168,600 in 2024, but Medicare continues on all income).

Your employer also pays matching amounts for both payroll taxes—they contribute an equal 6.2% for Social Security and 1.45% for Medicare on your behalf. This employer contribution does not appear on your pay stub as money you receive, but it is part of your total compensation cost to the company.

Key Takeaways

  • Income tax withholding is based on your total earnings and your W-4 choices, while payroll taxes are a fixed percentage that does not change.
  • Income taxes fund general federal and state government operations; payroll taxes fund only Social Security and Medicare.
  • Social Security payroll tax stops once you reach $168,600 in annual earnings (in 2024), but Medicare payroll tax continues on all income above that.
  • Your employer matches your payroll tax contributions dollar-for-dollar, but does not match income tax withholding.
  • Self-employed people pay both the employee and employer share of payroll taxes, which is why their self-employment tax is roughly double what an employee pays.

How income tax withholding works

Income tax withholding is an estimate. Your employer uses the W-4 form you completed to calculate how much federal income tax to remove from each paycheck. The W-4 asks about your filing status, number of dependents, and other income sources so the employer can predict roughly how much you will owe at tax time.

The amount withheld is not a fixed percentage—it depends on your tax bracket, which changes based on your total annual income. If you earn $35,000 a year, your withholding rate is different from someone earning $75,000. The IRS publishes withholding tables that employers use to calculate the right amount for each paycheck.

If your employer withholds too much, you get a refund when you file your tax return. If too little is withheld, you owe money. This is why changing your W-4 mid-year—if you get a raise, get married, or have a major life change—can adjust how much comes out of future paychecks.

How payroll taxes work

Payroll taxes are simpler: the rate is the same for everyone, and it does not change based on your income level. You pay 6.2% for Social Security and 1.45% for Medicare on every dollar you earn, up to the Social Security wage base ($168,600 in 2024). Once you cross that threshold, Social Security tax stops, but Medicare continues.

Your employer withholds these amounts automatically and sends them to the IRS along with their matching contribution. You do not fill out a form to change your payroll tax rate—it is determined by federal law. The only exception is if you are a member of certain religious groups that have been granted exemption, which is rare and requires specific IRS approval.

Payroll taxes appear on your pay stub as "FICA" (Federal Insurance Contributions Act). The Social Security portion funds your future retirement benefits and disability insurance. The Medicare portion funds your health insurance once you turn 65 and also covers some disabled people under 65.

Why the Social Security wage base matters

The Social Security wage base is a cap on how much of your income gets taxed for Social Security. In 2024, that cap is $168,600. This means if you earn $200,000 a year, you only pay Social Security tax on the first $168,600 of that income. The remaining $31,400 is not subject to Social Security tax.

This cap changes every year based on wage growth in the economy. It was $160,200 in 2023 and $168,600 in 2024. The IRS announces the new cap each October for the following year.

Medicare has no wage base cap. You pay 1.45% on every dollar you earn, no matter how high your income goes. High earners also pay an additional 0.9% Medicare tax on income above $200,000 (single filers) or $250,000 (married filing jointly), which was added in 2013.

State and local income taxes

Most states also collect income tax, and some cities do as well. State income tax works similarly to federal income tax—your employer withholds an amount based on your state W-4 form and your estimated state tax liability. Nine states have no state income tax: Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming, and New Hampshire (which taxes only dividend and interest income).

State income tax rates vary widely. Some states have a flat rate (like Illinois at 4.95%), while others use a progressive system with multiple brackets like the federal system. Your state withholding appears separately on your pay stub from federal withholding.

Payroll taxes (Social Security and Medicare) are always federal only—states do not collect their own versions of these taxes.

Self-employed people and payroll taxes

If you are self-employed, you pay both the employee and employer share of payroll taxes, which is called self-employment tax. This means you pay 12.4% for Social Security (instead of 6.2%) and 2.9% for Medicare (instead of 1.45%), for a total of 15.3% on your net self-employment income.

You calculate self-employment tax on Schedule SE when you file your tax return. You can deduct half of your self-employment tax as a business expense, which reduces your taxable income slightly. You still owe federal income tax on your self-employment income as well, calculated the same way as an employee would.

Self-employed people typically make quarterly estimated tax payments to the IRS for both income tax and self-employment tax, rather than having an employer withhold throughout the year.

What happens to the money you pay

Income tax goes into the general U.S. Treasury and funds federal government operations: military, federal agencies, infrastructure, interest on the national debt, and other programs. Some of that money also goes to states and cities through federal grants.

Social Security tax goes into the Social Security Trust Fund. When you retire, become disabled, or die, your benefits are paid from this fund. The amount you receive is based on your earnings history and age when you claim, not on how much you paid in.

Medicare tax goes into the Medicare Trust Fund, which pays for hospital insurance (Part A) and is used to subsidize other Medicare parts. Like Social Security, your Medicare coverage is not directly tied to how much you paid in—it is available to anyone 65 and older, regardless of their tax history.

Frequently Asked Questions

Why do I pay both income tax and payroll taxes?

They fund different things. Income tax supports general government operations. Payroll taxes fund only Social Security and Medicare, which are insurance programs you pay into during your working years. Congress set them up as separate systems so Social Security and Medicare funding would not compete with other government spending.

Can I reduce my payroll taxes like I can reduce income tax?

No. Payroll tax rates are fixed by law and do not change based on your income, deductions, or filing status. Income tax withholding can be adjusted by changing your W-4, but payroll taxes cannot be reduced unless you fall below the wage base for Social Security or may have access to for a specific religious exemption.

What if I work for two employers in the same year?

Both employers will withhold Social Security tax up to the wage base limit. If your combined earnings exceed $168,600, you may overpay Social Security tax. You can claim a credit for the overpayment when you file your tax return. Income tax withholding from both jobs is combined when you file, and you may owe or receive a refund depending on your total withholding.

Do I get back the payroll taxes I paid?

Not directly. Social Security and Medicare are insurance programs, not savings accounts. You receive Social Security retirement benefits based on your age and earnings history, and Medicare coverage at 65. If you die before claiming Social Security, your family may receive survivor benefits. If you never claim, the money does not go back to you or your heirs.

Why is my Medicare tax higher than it used to be?

If your income crossed $200,000 (single) or $250,000 (married filing jointly), you now owe an additional 0.9% Medicare tax on the income above that threshold. This was added in 2013 as part of the Affordable Care Act. Your employer withholds this automatically if your income exceeds the threshold.