2018 Federal Payroll Tax Rates Calculator

Estimate 2018 employee and employer federal payroll taxes using the key FICA rules in effect for 2018, including Social Security, Medicare, Additional Medicare Tax, and an optional FUTA estimate.

Expert Guide to the 2018 Federal Payroll Tax Rates Calculator

A 2018 federal payroll tax rates calculator helps employers, payroll managers, bookkeepers, and employees estimate how much of a worker’s pay is subject to federal payroll taxes for the 2018 tax year. While many people casually use the term “payroll tax” to mean all deductions from a paycheck, federal payroll taxes are usually focused on the taxes that fund Social Security and Medicare under the Federal Insurance Contributions Act, or FICA. Depending on the context, some users also want to estimate Federal Unemployment Tax Act liability, known as FUTA, because it is a federal payroll tax paid by employers.

This calculator is designed to estimate the most widely referenced 2018 federal payroll tax components. Specifically, it calculates the employee share of Social Security tax, the employee share of Medicare tax, the employee’s Additional Medicare Tax when income exceeds the applicable threshold, the employer’s matching Social Security and Medicare taxes, and an optional FUTA estimate. It is useful when you want a clean snapshot of payroll tax cost before running payroll, preparing annual compensation budgets, reviewing historical 2018 payroll records, or validating old payroll reports.

For 2018, the Social Security wage base was $128,400. Wages above that limit were not subject to the 6.2% Social Security tax, but they still remained subject to Medicare tax.

What federal payroll taxes applied in 2018?

For most wage earners in 2018, federal payroll taxes included two main FICA components:

• Social Security tax: 6.2% paid by the employee and 6.2% paid by the employer, but only on wages up to the annual wage base.
• Medicare tax: 1.45% paid by the employee and 1.45% paid by the employer on all covered wages, with no wage base cap.

There was also an Additional Medicare Tax of 0.9% on the employee side only for wages and compensation above the applicable threshold. This tax was not matched by the employer. In addition, employers could owe FUTA, generally at 6.0% on the first $7,000 of wages per employee, but in many cases reduced to an effective 0.6% rate after the maximum 5.4% state unemployment tax credit.

2018 Federal Payroll Tax	Employee Rate	Employer Rate	Wage Limit / Threshold	Key Rule
Social Security	6.2%	6.2%	$128,400 wage base	Applies only up to the annual Social Security wage base.
Medicare	1.45%	1.45%	No cap	Applies to all covered wages.
Additional Medicare	0.9%	0%	Threshold based on filing status	Employee only, no employer match.
FUTA	0%	6.0% before credits	First $7,000 of wages	Often reduced to 0.6% effective rate with full 5.4% credit.

2018 Additional Medicare Tax thresholds

Unlike Social Security tax, Additional Medicare Tax is not subject to a wage base. Instead, it begins once wages exceed a threshold tied to filing status for the individual taxpayer. These thresholds matter when estimating final tax liability. In live payroll administration, employers generally begin withholding Additional Medicare Tax once an employee’s wages exceed $200,000, regardless of filing status. However, for annual personal tax estimation, filing status is the more informative lens.

Filing Status	2018 Additional Medicare Threshold	Additional Rate Above Threshold
Single	$200,000	0.9%
Head of household	$200,000	0.9%
Qualifying widow(er)	$200,000	0.9%
Married filing jointly	$250,000	0.9%
Married filing separately	$125,000	0.9%

How the calculator works

The logic behind this 2018 federal payroll tax rates calculator is straightforward and follows the 2018 federal rules:

1. It reads the annual taxable wages entered by the user.
2. It applies the 6.2% Social Security rate to wages up to $128,400.
3. It applies the 1.45% Medicare rate to all wages for both the employee and employer.
4. It checks the filing-status threshold and applies the 0.9% Additional Medicare Tax to wages above that amount for the employee.
5. If selected, it estimates FUTA based on 6.0% less the user-entered state unemployment credit, limited to the first $7,000 of wages.
6. It divides the employee payroll tax by the selected number of pay periods to estimate a per-paycheck amount.

This means the calculator is especially useful for back-of-the-envelope forecasting and historical review. It does not replace full payroll software because actual withholding can vary when payroll is processed period by period, when pretax deductions reduce taxable wages, or when an employer is located in a FUTA credit reduction state.

Example using 2018 rates

Suppose an employee earned $75,000 in covered wages during 2018. Because that amount is below the $128,400 Social Security wage base, the full salary is subject to Social Security tax. The employee pays 6.2% for Social Security and 1.45% for Medicare. The employer pays the same 6.2% and 1.45%. Since $75,000 is below the Additional Medicare threshold for all filing statuses listed above, no Additional Medicare Tax is due.

• Employee Social Security: $75,000 × 6.2% = $4,650
• Employee Medicare: $75,000 × 1.45% = $1,087.50
• Employee Additional Medicare: $0
• Employer Social Security: $4,650
• Employer Medicare: $1,087.50

If FUTA is included and the employer qualifies for the maximum 5.4% credit, the net effective FUTA rate is 0.6% on the first $7,000. That produces an employer FUTA cost of $42 for that employee. The calculator above handles this automatically when the FUTA option is enabled.

Why the Social Security wage base matters so much

The wage base has one of the biggest effects on payroll tax calculations for higher earners. In 2018, only the first $128,400 of wages was subject to Social Security tax. This cap means that someone earning $300,000 does not continue paying the 6.2% Social Security tax on the full amount. Instead, both the employee and employer stop incurring new Social Security tax once wages exceed the annual base. Medicare, however, continues without a cap, and Additional Medicare may start for the employee.

This difference is one reason many payroll cost models break out Social Security and Medicare separately rather than simply grouping them into one FICA line. From a budgeting perspective, high-income employees often have a lower effective Social Security rate across their total annual income because the cap has been reached, while their Medicare burden continues to rise.

What this calculator includes and what it does not include

This page is focused on the major federal payroll tax rates associated with 2018 wage compensation. It does include the core FICA taxes and an optional FUTA estimate. However, users should understand the boundaries of the estimate.

Included in this calculator:

• 2018 employee Social Security tax
• 2018 employer Social Security tax
• 2018 employee Medicare tax
• 2018 employer Medicare tax
• 2018 employee Additional Medicare Tax estimate based on filing status
• Optional employer FUTA estimate

Not included in this calculator:

• Federal income tax withholding under IRS wage-bracket or percentage methods
• State income tax withholding
• State unemployment insurance taxes
• Local payroll taxes
• Pretax retirement, cafeteria plan, or health benefit adjustments
• Household employee special rules, agricultural payroll exceptions, or church exemptions

Best practices when using a 2018 payroll tax estimator

If you are reviewing historical payroll data, enter annual wages that were actually subject to Social Security and Medicare. If pretax deductions reduced taxable wages, using gross salary alone may overstate payroll tax. If you are analyzing employer cost, remember that FUTA depends on state unemployment tax credits and can differ for credit reduction states. If you are estimating the employee’s year-end tax position, the filing-status-based Additional Medicare threshold can be more accurate than employer withholding alone.

For many small businesses, this kind of calculator is helpful for compensation planning. If you are deciding whether a raise, bonus, or new hire changes payroll burden, the calculator gives a practical annual estimate. For employees, it can help explain why paycheck taxes change after the Social Security wage base is reached or why very high income can trigger Additional Medicare Tax.

Authoritative 2018 payroll tax references

For deeper research and primary-source verification, review these official resources:

• IRS Publication 15 (Circular E), Employer’s Tax Guide for 2018
• Social Security Administration contribution and benefit base history
• IRS Topic No. 560, Additional Medicare Tax

Common questions about 2018 federal payroll taxes

Is federal income tax withholding the same as payroll tax? Not exactly. Income tax withholding appears on paychecks, but payroll tax usually refers to Social Security, Medicare, and sometimes unemployment taxes. This calculator focuses on those payroll taxes rather than federal income tax withholding formulas.

Does the employer match Additional Medicare Tax? No. The employer matches the regular 1.45% Medicare tax, but not the 0.9% Additional Medicare Tax.

Why does filing status matter for Additional Medicare Tax? Because the actual tax threshold for year-end liability depends on the worker’s filing status. For example, married taxpayers filing jointly generally have a higher threshold than single taxpayers.

Why might my payroll software show a slightly different result? Full payroll systems often calculate tax per payroll run, apply rounding conventions, account for pretax deductions, handle multiple payroll periods, and use employer withholding rules for Additional Medicare Tax. A simple annual estimator may differ slightly from a live payroll engine.

Final takeaway

The 2018 federal payroll tax rates calculator above is built to give a reliable estimate of the key federal payroll tax obligations tied to wages in 2018. For most users, the most important figures are the 6.2% Social Security rate up to $128,400, the 1.45% Medicare rate on all wages, the 0.9% Additional Medicare Tax above the applicable threshold, and the employer-side FUTA estimate when relevant. When used with accurate taxable wage data, it offers a fast and practical way to understand both employee deductions and employer payroll cost for the 2018 tax year.