Payroll tax is money your employer withholds from your paycheck and sends to the federal government

When you see your paycheck, the gross amount (what you earned) is larger than the net amount (what you take home). The difference includes federal income tax withholding, Social Security tax, and Medicare tax. These three categories make up payroll tax. Your employer calculates how much to withhold based on information you provide on Form W-4, then sends that money directly to the Internal Revenue Service (IRS) on your behalf.

Payroll tax is separate from income tax you might owe at the end of the year. The withholding is an advance payment toward that tax bill. If your employer withholds too much, you get a refund when you file your tax return. If too little is withheld, you owe the difference.

Your employer also pays a matching amount of Social Security and Medicare tax — money that comes from the employer's budget, not your paycheck. This employer portion does not appear on your stub, but it is part of the total payroll tax system.

Key Takeaways

  • Payroll tax consists of federal income tax withholding, Social Security tax (6.2% of wages up to an annual cap), and Medicare tax (1.45% of all wages).
  • Your employer withholds these amounts from each paycheck and sends them to the IRS, based on the W-4 form you completed when hired.
  • Social Security and Medicare taxes are also paid by your employer in matching amounts, though you only see your half on your pay stub.
  • The amount withheld is not final — it is an estimate that gets reconciled when you file your tax return each year.
  • Self-employed people pay both the employee and employer portions of Social Security and Medicare tax, called self-employment tax.

How much Social Security and Medicare tax comes out of your paycheck

Social Security tax is 6.2% of your wages, but only up to a wage cap that changes each year. In 2024, that cap is $168,600, meaning once you earn that much in a calendar year, no more Social Security tax is withheld from your paychecks for the rest of that year. Medicare tax is 1.45% of all your wages with no cap — it continues no matter how much you earn.

If you earn over $200,000 as a single filer (or $250,000 if married filing jointly), an additional 0.9% Medicare tax is withheld on the amount above that threshold. This is called the Net Investment Income Tax in some contexts, though on a paycheck it appears as Additional Medicare Tax.

These percentages are set by federal law and do not change based on your personal situation. Everyone with W-2 wages pays the same rates.

Federal income tax withholding and Form W-4

Federal income tax withholding is different from Social Security and Medicare tax because the amount depends on your personal circumstances. When you start a job, you fill out Form W-4, which asks about your filing status, number of dependents, other income, and whether you have a spouse who also works. Your employer uses this information to calculate how much federal income tax to withhold from each paycheck.

If your life changes — you get married, have a child, take a second job, or your spouse's income changes — you can submit a new W-4 to adjust your withholding. The IRS provides a withholding calculator on its website to help you figure out whether your current withholding is roughly correct.

Withholding too much means you give the government an interest-free loan all year and get a refund in April. Withholding too little means you might owe money when you file, or face penalties if you owe more than $1,000. Most people aim for withholding that results in a small refund or a small amount owed, rather than a large swing either way.

Why payroll tax exists and where the money goes

Payroll tax funds three federal programs: Social Security (the retirement and disability insurance program), Medicare (health insurance for people 65 and older), and general federal income tax revenue (which funds defense, infrastructure, and other government operations).

Social Security tax you pay now goes into a trust fund that pays current retirees and disabled workers. When you retire, your own Social Security benefit is based on how much you paid in over your working years. Medicare tax similarly funds the Medicare program, which you become may be able to access for at age 65 regardless of income.

Federal income tax withholding is not earmarked for a specific program — it goes into the general Treasury to fund whatever Congress appropriates money for that year.

How payroll tax differs for self-employed people

If you are self-employed, you pay both the employee and employer portions of Social Security and Medicare tax yourself. This is called self-employment tax, and it totals 15.3% (12.4% for Social Security up to the wage cap, plus 2.9% for Medicare). You calculate it on Schedule SE and pay it when you file your tax return, or in quarterly estimated tax payments if you expect to owe more than $1,000.

Self-employed people do not have an employer to withhold federal income tax, so they must also make quarterly estimated tax payments for federal income tax. The IRS provides Form 1040-ES to help calculate these payments.

Self-employed people can deduct half of their self-employment tax as an above-the-line deduction on their tax return, which reduces their taxable income slightly.

What happens if your employer withholds the wrong amount

If your employer withholds too much payroll tax, you will receive a refund when you file your tax return. The IRS processes most refunds within 21 days of accepting your return, though it can take longer if you claim certain credits or if your return is selected for review.

If your employer withholds too little, you will owe the difference when you file. If you owe more than $1,000, you may also owe a penalty for underpayment of estimated tax, unless you had a good reason for the shortfall (such as a job change mid-year or a major life event).

You can check your payroll tax record anytime by creating an account on irs.gov and viewing your tax transcript. This shows how much your employer reported you earned and how much was withheld, which you can compare to your pay stubs to catch errors.

Payroll tax on tips, bonuses, and other income

Payroll tax applies to all wages and salaries, including tips you report to your employer, bonuses, commissions, and severance pay. Your employer withholds payroll tax on these the same way as regular wages.

If you receive cash tips that you do not report to your employer, no payroll tax is withheld, but you are still legally required to report them on your tax return and pay income tax and self-employment tax on them. Many workers underreport tips, which can result in an IRS audit.

Some types of income do not have payroll tax withheld: interest, dividends, rental income, and income from a side business (unless you are an employee of that business). You may owe income tax on these, but you pay it through quarterly estimated tax payments or when you file your return, not through payroll withholding.

Frequently Asked Questions

Why do I pay Social Security tax if I might not collect Social Security?

Social Security tax funds current retirees and disabled workers, not just future benefits for you. Even if you do not collect Social Security later, your payments support the program for others. Additionally, Social Security provides disability and survivor benefits — if you become disabled or die, your family may receive benefits based on your earnings record.

Can I reduce my payroll tax withholding?

You can adjust your federal income tax withholding by submitting a new Form W-4 to your employer. You cannot reduce Social Security or Medicare tax — those rates are set by law. However, certain retirement contributions (like a 401(k) or traditional IRA) reduce your taxable wages, which lowers your federal income tax withholding.

What if I work for two employers at the same time?

Each employer withholds federal income tax based on the W-4 you gave them, without knowing about your other job. This often results in under-withholding because each employer thinks you are earning less than you actually are. You can adjust this by submitting a new W-4 to one or both employers, or by making a large estimated tax payment when you file your return.

Do I pay payroll tax on unemployment benefits?

Unemployment benefits are subject to federal income tax withholding if you request it, but they are not subject to Social Security or Medicare tax. When you explore for unemployment, you can choose whether to have federal income tax withheld. If you do not, you may owe income tax when you file your return.

Is payroll tax the same as income tax?

No. Payroll tax includes Social Security and Medicare tax (which are separate from income tax) plus federal income tax withholding. Social Security and Medicare are dedicated taxes that fund specific programs. Federal income tax withholding is an advance payment on your annual income tax bill. Together, they make up the total payroll tax system.