Payroll taxes are amounts withheld from a W-2 employee's gross wages each pay period and sent to the IRS. The main federal components are Social Security tax at 6.2%, Medicare tax at 1.45%, and federal income tax withholding based on your Form W-4. Employers match the Social Security and Medicare rates and pay them separately. Federal income tax withholding is not a flat rate. It varies by filing status and pay frequency.
- For 2025, the Social Security rate is 6.2% on wages up to $176,100. Medicare is 1.45% on all wages with no cap.
- Federal income tax withholding is not a fixed percentage. It is calculated from your W-4 filing status and pay frequency using IRS Publication 15-T bracket tables.
- Employers match your 6.2% Social Security and 1.45% Medicare payments. Those employer contributions do not appear on your pay stub.
- Pre-tax deductions such as 401(k) contributions reduce the wages subject to income tax withholding but do not reduce FICA taxes.
- Two workers with identical salaries can take home different amounts due to filing status, W-4 elections, state taxes, and benefit elections.
What Do Payroll Taxes Usually Include?
The term "payroll taxes" is used in two ways. In the strict legal sense, payroll taxes are FICA taxes: Social Security and Medicare. In everyday usage, the term often refers to all amounts withheld from a paycheck, including federal income tax.
The components most W-2 employees see on a pay stub are as follows:
| Component | Who Pays | Rate (2025) | Wage Cap |
|---|---|---|---|
| Social Security | Employee + Employer (each) | 6.2% | $176,100 |
| Medicare | Employee + Employer (each) | 1.45% | None |
| Additional Medicare Tax | Employee only | 0.9% | Wages over $200K ($250K MFJ) |
| Federal Income Tax Withholding | Employee only | Varies | None |
| State Income Tax Withholding | Employee only | Varies by state | Varies |
| Local Income Tax | Employee only | Varies by city | Varies |
| FUTA (Federal Unemployment) | Employer only | 0.6% effective | First $7,000 per employee |
Federal Income Tax Withholding
Federal income tax withholding is not a flat rate. Your employer uses IRS Publication 15-T to estimate your annual tax liability and divide it across your pay periods. The calculation starts with your gross wages, subtracts any pre-tax deductions, and applies the tax bracket tables to the remaining taxable wages. Your Form W-4 filing status determines which bracket table applies.
Social Security and Medicare (FICA)
FICA taxes are fixed-rate taxes. They do not depend on your W-4 elections. Social Security is 6.2% on wages up to $176,100 for 2025. After that threshold, Social Security withholding stops for the calendar year. Medicare is 1.45% on all wages with no cap. Employees earning above $200,000 in a calendar year pay an additional 0.9% Medicare surtax on the excess.
State and Local Income Tax
Nine states have no state income tax on wages for TY 2025: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. Employees in other states see state income tax withholding on every paycheck. Rates and calculation methods vary by state. Some cities also impose local income taxes, particularly in Ohio, Pennsylvania, New York City, and Detroit.
Payroll Tax vs. Income Tax: What Is the Difference?
The confusion between these two terms is common. Here is the practical distinction.
Payroll taxes, in the strict sense, are Social Security and Medicare. They are fixed-rate taxes that fund federal entitlement programs. They apply to every covered employee at the same rates regardless of income level (up to the Social Security wage base). They are defined under the Federal Insurance Contributions Act.
Income tax withholding is a different mechanism. It is an estimate of the employee's annual federal income tax liability, collected in advance by the employer and remitted to the IRS. The exact amount depends on the employee's W-4 elections, filing status, and pay frequency. At the end of the year, the actual tax liability is reconciled on Form 1040. If too much was withheld, the employee receives a refund. If too little, the employee owes the balance.
Both appear as deductions on a pay stub. Both are remitted to the IRS. But they are separate taxes with separate legal frameworks. When someone asks "how do payroll taxes work," they often mean all taxes withheld from a paycheck, not just FICA.
What Comes Out of a Paycheck, and in What Order?
Understanding the sequence matters because some deductions change the taxable wage base used for other calculations.
| Step | Item | Example: $2,000 Gross |
|---|---|---|
| 1 | Gross wages | $2,000.00 |
| 2 | Pre-tax deductions (401k, health insurance) | −$200.00 (example) |
| 3 | Taxable wages for income tax withholding | $1,800.00 |
| 4 | Federal income tax withholding | −$130.00 (approx., varies) |
| 5 | Social Security (6.2% of gross wages) | −$124.00 |
| 6 | Medicare (1.45% of gross wages) | −$29.00 |
| 7 | State income tax withholding | −$60.00 (example, varies) |
| 8 | Post-tax deductions (Roth 401k, garnishments) | −$0.00 |
| 9 | Net pay | $1,457.00 (approx.) |
Note the key distinction in step 2 and steps 5 through 6. Social Security and Medicare are calculated on gross wages, not on taxable wages. Pre-tax deductions reduce the income tax withholding base but do not reduce FICA.
This means a $200 biweekly 401(k) contribution saves approximately $32 in federal income tax (at the 22% marginal rate) but does not change the $153 in Social Security and Medicare owed on the full $2,000.
Why Do Two People With the Same Salary Have Different Paychecks?
FICA rates are identical for all covered employees. Federal income tax withholding is not. Here are the most common reasons two workers earning the same annual salary can take home different net amounts.
Filing Status
An employee using the Single withholding table will see higher federal withholding than an employee using the Married Filing Jointly table at the same income level. This is the single biggest driver of withholding differences among employees earning the same salary.
W-4 Dependent Credits (Step 3)
Step 3 of the Form W-4 lets employees claim dependent tax credits, which reduce the annual tax estimate used to calculate withholding. An employee claiming $4,000 in dependent credits (two qualifying children) will have noticeably lower withholding each period than an employee claiming nothing, even at the same gross pay and filing status.
Pre-Tax Benefit Elections
Employees who contribute to a 401(k), 403(b), or Section 125 health insurance plan reduce their taxable wages for income tax purposes. The more an employee contributes pre-tax, the lower the federal income tax withholding. Two employees earning $60,000 per year can have withholding that differs by $1,000 or more annually based on benefit elections alone.
Pay Frequency
A weekly paycheck and a biweekly paycheck from the same annual salary produce different per-period withholding because the IRS bracket tables are applied to the per-period wages and then converted to an annualized amount. The math equalizes across the full year, but individual checks look different.
State and Local Taxes
An employee in Texas and an employee in California with identical salaries have very different net pay. California's marginal income tax rates reach 9.3% for middle income earners. Texas has no state income tax. State withholding differences routinely account for hundreds of dollars per paycheck for employees in high-tax states.
Extra Withholding Elections
Step 4(c) of the W-4 allows employees to request additional withholding per period. An employee preparing for a large tax liability from freelance income or an investment sale may add $50 or $200 per period in extra withholding. This reduces net pay intentionally.
Enter your hourly rate or annual salary to see a full paycheck breakdown including federal withholding and FICA for 2025.
Employee Taxes vs. Employer Taxes: What Workers Usually Don't See
A pay stub shows the taxes deducted from the employee's wages. It does not show what the employer pays on top.
What Employees Pay
The employee pays: Social Security at 6.2%, Medicare at 1.45%, and federal income tax withholding at a variable rate. State and local income taxes apply where applicable. These amounts reduce the employee's gross pay to arrive at net pay.
What Employers Pay Separately
Employers pay a matching 6.2% Social Security and 1.45% Medicare on every dollar of covered wages. These payments come entirely from the employer. The employee does not contribute to them and does not see them on a pay stub.
On a $52,000 annual salary, the employee pays $3,224 in Social Security and $754 in Medicare for a total of $3,978 in FICA. The employer pays the same $3,978 on top of the $52,000 salary. The true cost to the employer for that position is $55,978 in wages and FICA alone, before any benefits.
Employers also pay FUTA (Federal Unemployment Tax) at 0.6% on the first $7,000 of each employee's wages. That amounts to $42 per employee per year at the effective rate. State unemployment taxes (SUTA) are paid by employers as well, at rates that vary by state and employer experience rating.
Why This Matters
Understanding the employer side of payroll taxes is useful when negotiating compensation, evaluating a job offer, or operating a business. When an employer quotes a total compensation cost, the employer-side FICA adds approximately 7.65% on top of the first $176,100 of wages. For a $100,000 salary, that is an additional $7,650 per year in employer-side payroll taxes beyond the wages themselves.
How This Connects to the Payroll Calculators
Understanding the theory behind payroll taxes is useful. Seeing the exact numbers for your situation is more useful.
The hourly paycheck calculator takes your hourly rate, hours worked, and W-4 elections and produces a full per-period breakdown. It shows gross pay, each FICA line, federal income tax withholding calculated using the IRS Publication 15-T annualized percentage method, and estimated net pay. It handles the 2025 Social Security wage base and Additional Medicare Tax threshold.
The salary paycheck calculator does the same for salaried workers. Enter your annual salary, pay frequency, and filing status. The calculator outputs a per-period breakdown showing every federal withholding component. An optional state flat rate field covers states with a simple flat income tax rate.
If you have already received a paycheck and want to verify the deductions line by line, see the pay stub guide for a field-by-field explanation of every item on a standard earnings statement.
For a focused explanation of FICA specifically, including the wage base mechanics, employer matching, the Additional Medicare Tax threshold, and how FICA differs from income tax withholding, see the What Is FICA Tax guide.
Common Misunderstandings About Payroll Taxes
Withholding Is Not Your Final Tax Liability
Federal income tax withholding is an estimate. It is calculated each pay period based on your W-4 and pay. It does not account for investment income, rental income, self-employment income, itemized deductions, or tax credits you will claim at year-end. Your actual tax liability is determined when you file Form 1040. Withholding is simply a payment toward that liability, collected throughout the year.
Getting a Large Refund Means You Overpaid
A large refund is not a windfall. It means too much was withheld from each paycheck throughout the year. You effectively gave the IRS an interest-free loan. If you consistently receive large refunds, updating your W-4 to reduce withholding increases your per-period net pay instead.
Pre-Tax Deductions Reduce All Taxes
Pre-tax deductions such as traditional 401(k) contributions and Section 125 health insurance premiums reduce the wages subject to federal income tax withholding. They do not reduce Social Security or Medicare wages. The FICA base is gross wages in most cases.
Gross Pay and Taxable Wages Are the Same Number
They are often different. If you contribute $400 per paycheck to a 401(k) and $150 to an employer health plan through a Section 125 arrangement, your taxable wages for income tax purposes are $550 lower than your gross wages. The federal withholding is calculated on the reduced amount, not the gross.
All Paychecks Should Be Identical
For salaried employees, gross pay per period is generally fixed. But net pay can change across the year for several reasons: the Social Security wage base stopping partway through the year, mid-year W-4 updates, changes to benefit elections, and state tax adjustments. A salaried employee's last several paychecks of the year often show higher net pay because Social Security withholding stops after $176,100 in wages.
At LMN Tax Inc, we frequently see clients surprised by a balance due at filing time, even after a year of consistent withholding. The cause is usually one of three things: a second W-2 job that pushed total income into a higher bracket, a W-4 that was last updated years before a raise, or investment income that was never factored into withholding at all. Federal income tax withholding is only as accurate as the information on the W-4. If your financial situation changed during the year, the withholding calculated in January may be wrong by December.
Real-World Example: Sara's Biweekly Paycheck
Sara earns $52,000 per year. She is paid biweekly (26 pay periods). She files Single with no additional W-4 credits. She lives in Texas, which has no state income tax. She contributes nothing pre-tax.
Gross pay per period: $52,000 / 26 = $2,000.00
- Social Security (6.2%): $124.00
- Medicare (1.45%): $29.00
- Federal income tax withholding (Pub 15-T, 2020+ W-4, Standard Withholding, Single, TY 2025): approximately $162.00
- State income tax: $0.00 (Texas)
Total deductions from Sara's paycheck: $315.00. Estimated net pay: $1,685.00.
Her employer simultaneously remits its own $124.00 in Social Security and $29.00 in Medicare to the IRS. Sara never sees this, but the employer's true labor cost for her is approximately $2,153 per pay period, not $2,000.
If Sara had added a $300 biweekly 401(k) contribution, her federal income tax withholding would drop to approximately $96 (22% marginal rate saving on $300 = $66 less). But her Social Security and Medicare would still be calculated on the $2,000 gross. Her net pay would be roughly $1,436: $2,000 minus $300 (401k) minus $96 (federal) minus $124 (SS) minus $29 (Medicare).
Use the salary paycheck calculator to run these exact scenarios with your own numbers and pay frequency.
When This May Not Apply
- Self-employed workers: Freelancers, independent contractors, and sole proprietors are not subject to payroll tax withholding. They pay self-employment tax (15.3% on net earnings) through quarterly estimated payments. The SE tax covers both the employee and employer share of FICA.
- S-Corporation officer compensation: Shareholder-employees of S-Corps receive W-2 wages subject to FICA, but distributions above reasonable compensation are not subject to payroll taxes. Misclassifying distributions as wages or wages as distributions is an IRS audit area.
- FICA-exempt employment: Certain categories of workers are exempt from Social Security and Medicare withholding. These include some government employees covered by alternative pension systems, student employees of educational institutions under specific conditions, and certain nonresident aliens on specific visa types.
- Multiple employers: If you work for two employers simultaneously and each withholds Social Security on your wages, you may over-withhold on the combined total above $176,100. The excess Social Security is recovered as a credit on Form 1040 at year-end. Each employer withholds independently and does not coordinate with the other.
- Mid-year life changes: Marriage, divorce, a new dependent, a significant raise, or starting a side business can all make current withholding inaccurate. A W-4 update is required to adjust. Without it, the existing withholding continues unchanged regardless of what changed in your tax situation.
Frequently Asked Questions
Now that you understand how payroll taxes work, use the calculators to see the exact numbers for your situation. The hourly and salary paycheck calculators apply the 2025 IRS Publication 15-T withholding tables to your inputs and show each deduction line.
Estimate take-home pay with the Hourly Paycheck Calculator or run the Paycheck Calculator for a full 2025 withholding breakdown.
If you are an employer or business owner, the Employer Payroll Tax Obligations guide covers what you owe from your own funds: FICA matching, FUTA, deposit schedules, and the Trust Fund Recovery Penalty. Use the Payroll Tax Calculator to run the numbers: enter gross wages per period and your state SUTA rate to see total annual employment cost and effective employer tax burden.
For a focused explanation of how the Social Security component works — including the $176,100 wage base mechanics, what OASDI funds, and how employees with two jobs may overpay — see the Social Security Tax Explained guide.