What Are Payroll Deductions and How Do You Calculate Them?

July 30, 2025 By Becca Park
What Are Payroll Deductions and How Do You Calculate Them?
15:20

Running payroll might seem simple at first, but many business owners quickly realize there is more involved than expected. Between taxes, insurance, and other withholdings, knowing exactly what to deduct and how to do it right is critical. If you get it wrong, you could face penalties, legal issues, or frustrated employees.

As a business owner, you may be asking:

What are payroll deductions, and how do I calculate them?

Payroll deductions are amounts withheld from an employee’s paycheck to cover taxes, benefits, and other required contributions. These deductions directly affect what your employee takes home and must be calculated correctly every pay period.

At CMP, we help employers in Salt Lake City, Logan, and St. George stay compliant with federal and state payroll laws. Whether you are running payroll yourself or looking into outsourced options, we provide the clarity you need to make informed decisions through our comprehensive payroll and bookkeeping services.

In this article, you will learn what payroll deductions are, how they are calculated, which ones are mandatory, and which are optional. We will walk through real examples, common mistakes to avoid, and what every Utah employer needs to know.

What Are Payroll Deductions and How Do You Calculate Them

Understanding Payroll Deductions

Payroll deductions are amounts an employer withholds from an employee’s gross pay. These deductions cover required taxes, benefits, and other contributions. After deductions are applied, the remaining amount is referred to as net pay.

Payroll deductions matter because they affect employee take-home pay and help your business stay compliant with tax laws. As an employer, you are responsible for calculating and withholding the correct amounts each pay period.

In Utah, this includes federal income tax, Social Security, Medicare, and the state’s flat income tax rate. Voluntary deductions, such as health insurance or retirement contributions, may also apply depending on employee selections.

What is the Difference Between Gross Pay and Net Pay?

Gross pay is the total amount an employee earns before any deductions are made. This includes hourly wages, salary, bonuses, and commissions.

Net pay is what the employee receives after payroll deductions are subtracted. This is the actual paycheck amount deposited or issued.

Understanding the difference helps both you and your employees know how pay is calculated and ensures transparency in the payroll process.

What are the Two Types of Payroll Deductions?

There are two types of payroll deductions: mandatory and voluntary. Understanding the difference helps you calculate employee pay correctly and stay compliant with tax laws.

Mandatory payroll deductions

Mandatory deductions are required by law. As an employer, you must withhold these from every employee paycheck.

Common examples include:

  • Federal income tax
  • Utah state income tax
  • Social Security tax
  • Medicare tax
  • Court-ordered wage garnishments

These deductions help fund government programs and are non-negotiable for employees.

Voluntary payroll deductions

Voluntary deductions are optional and based on the employee’s choices. These may include benefits or contributions the employee has agreed to in writing.

Examples include:

Some voluntary deductions reduce taxable income. These are called pre-tax deductions. Examples include traditional 401(k) contributions and many health insurance premiums.

Others are post-tax deductions, which are taken out after taxes are calculated. Examples include Roth 401(k) contributions and certain insurance plans.

Understanding which deductions are pre-tax or post-tax helps you calculate taxes correctly and explain paycheck totals clearly to your team.

What Must Be Withheld from an Employee’s Paycheck?

As an employer, you are required by law to withhold certain deductions from every employee’s paycheck. These deductions fund government programs and enforce legal obligations. Missing or miscalculating them can result in fines or penalties for your business.

Federal income tax

Federal income tax must be withheld based on the employee’s most recent Form W‑4. The exact amount depends on filing status, income, and withholding elections. These funds go to the IRS to support federal programs.

Utah state income tax

Utah has a flat state income tax rate, which changed in 2025. From January 1 through May 31, the rate was 4.55 percent. Starting June 1, 2025, the rate dropped to 4.50 percent. Employers must apply the correct rate depending on the paycheck date.

Social Security and Medicare (FICA)

You must withhold FICA taxes from each paycheck, including:

  • 6.2 percent for Social Security (up to the annual wage limit)
  • 1.45 percent for Medicare (no wage cap)

Employers also pay an equal matching contribution, but only the employee portion is withheld from their pay.

Court‑ordered garnishments

If you receive a legal order, you must withhold wages for child support, tax levies, or other garnishments. These withholdings are mandatory and must be processed accurately and on time.

What Are Voluntary Payroll Deductions, and What Can Employers Offer?

Voluntary payroll deductions are amounts employees choose to have withheld from their paychecks. Employers offer these options to support benefits, savings, or charitable giving.

Here are clear examples of voluntary payroll deductions:

  • Retirement contributions: Employees may elect to contribute to 401(k) or IRA accounts. Traditional 401(k) contributions are taken pre-tax, reducing taxable income. Roth 401(k) contributions are post-tax.
  • Health, dental, and vision insurance: Many employers deduct premiums directly from pay. These premiums are usually taken pre-tax, which lowers taxable income.
  • Life and disability insurance: Employees can opt into policies for financial protection. These premiums are typically taken post-tax unless the plan is qualified.
  • Charitable donations: Payroll giving programs let employees support charities regularly and conveniently.
  • Union dues: If employees are in a union, dues can be deducted directly from their pay.

These deductions enhance your benefits package and give employees flexibility. You must obtain written authorization before withholding any voluntary deductions. Processing them accurately and consistently maintains compliance and builds trust with your team.

How to Calculate Payroll Deductions (Step-by-Step)

If you are running payroll in-house, knowing how to calculate deductions accurately is essential. It ensures your employees are paid correctly and that your business stays compliant with federal and Utah payroll laws.

Here is a simple step-by-step process to follow when calculating payroll deductions:

Step 1: Start with gross pay

Begin with the employee’s total earnings before any deductions. This includes regular wages, bonuses, commissions, or overtime.

Step 2: Subtract pre-tax voluntary deductions

Next, subtract any voluntary deductions that reduce taxable income. These can include health insurance premiums, traditional 401(k) contributions, or health savings account deposits. Pre-tax deductions lower the amount of income that is subject to tax.

Step 3: Apply federal and state income tax

Calculate the federal income tax based on the employee’s Form W-4 and IRS tax tables. Then apply Utah’s flat state income tax rate, which is 4.5 percent as of June 2025. Be sure to use the correct rate based on the paycheck date.

Step 4: Subtract FICA taxes

Withhold 6.2 percent for Social Security up to the annual wage cap and 1.45 percent for Medicare with no cap. If the employee earns over $200,000 annually, apply the additional Medicare tax. These taxes are required by federal law.

Step 5: Subtract post-tax deductions

Finally, remove any post-tax deductions. These may include Roth 401(k) contributions, court-ordered wage garnishments, or certain insurance premiums that do not reduce taxable income.

Step 6: The result is net pay

What remains after all deductions is the employee’s net pay. This is the amount they actually receive in their paycheck.

Example:

Let’s say an employee earns $4,000 in gross monthly pay.

  • Health insurance (pre-tax): $200
  • 401(k) contribution (pre-tax): $300
  • Taxable income: $3,500
  • Federal income tax: $350 (estimated)
  • Utah state income tax (4.5 percent): $157.50
  • Social Security (6.2 percent): $217
  • Medicare (1.45 percent): $50.75
  • No post-tax deductions

Net pay = $4,000 – $200 – $300 – $350 – $157.50 – $217 – $50.75 = $2,724.75

This is the amount the employee takes home after all required and voluntary deductions. If your business reimburses expenses through payroll, those amounts are typically added after calculating net pay. Using a structured process like this helps reduce errors and builds trust with your team. Whether you are handling payroll on your own or reviewing software reports, understanding how each deduction fits into the equation gives you more control and confidence.

Common Payroll Deduction Mistakes to Avoid

Managing payroll in-house can save money, but it also comes with serious responsibilities. If payroll deductions are handled incorrectly, your business could face penalties, compliance issues, or even damage to employee trust. Here are some of the most common payroll deduction mistakes employers should watch for.

Misclassifying employees and contractors

One of the most common errors is treating contractors as employees or the other way around. Independent contractors are responsible for their own taxes, while employees require withholding. Misclassification can lead to back taxes, interest, and penalties. Review IRS guidelines and make sure your records match how the work is actually performed.

Withholding too much or too little

Incorrectly calculating federal or state income tax can result in underpayment or overpayment. This affects the employee’s take-home pay and may create problems at tax time. Be sure to use the latest IRS tax tables and confirm that Form W-4 information is entered correctly.

Deducting employer-paid costs

Some payroll taxes are the employer’s responsibility and cannot be withheld from employee pay. For example, federal unemployment tax (FUTA), Utah unemployment insurance, and workers' compensation premiums must be paid by the employer. Withholding these costs from an employee’s check is not allowed and may lead to compliance issues.

Missing tax payment or filing deadlines

Failing to deposit withheld taxes on time or missing a filing deadline can result in interest charges and penalties. Federal tax deposits and Utah state filings have specific schedules depending on your payroll frequency. Make sure you understand your due dates and file consistently.

By avoiding these common payroll deduction mistakes, you can protect your business from fines and build a reliable payroll system. Clear records, up-to-date information, and attention to detail are essential parts of your payroll responsibilities as an employer.

Do Payroll Deductions Vary by State?

Yes, payroll deductions can vary by state. Each state sets its own tax rules, benefit programs, and employer responsibilities. Some states have progressive income tax brackets, local payroll taxes, or additional insurance requirements that affect how deductions are calculated.

In Utah, payroll deduction laws are simpler than in many other states. Utah uses a flat state income tax rate of 4.0 percent as of June 2025. This means all employees are taxed at the same rate, regardless of income level. Employers must withhold this amount from each paycheck unless the employee qualifies for an exemption.

Utah does not have local payroll taxes, which are required in some cities and counties in other states. This makes payroll withholding more straightforward for Utah employers.

While federal payroll rules apply in all states, understanding the specific requirements in your state helps ensure accurate withholding and compliance. For Utah businesses, staying updated on state tax rates and withholding rules is a key part of managing payroll correctly.

Frequently Asked Questions About Payroll Deductions

Below are some of the most common questions we hear from employers handling payroll in-house or reviewing outsourced options.

What are examples of payroll deductions?

Payroll deductions include any amounts withheld from an employee’s paycheck. Examples include federal and state income taxes, Social Security, Medicare, health insurance premiums, retirement contributions, and court-ordered garnishments. Some deductions are required by law, while others are based on employee choices.

What items cannot be deducted from employee pay?

Employers cannot deduct costs that are their responsibility, such as federal unemployment tax (FUTA), state unemployment insurance, or workers' compensation premiums. These must be paid by the employer and cannot be passed to the employee.

What is the average payroll deduction percentage?

While it varies by employee and benefits selected, payroll deductions often reduce gross pay by about 25 to 30 percent. This includes income taxes, FICA, and common voluntary deductions. Actual percentages depend on wages, withholding elections, and benefit plans.

Which payroll deductions are exempt from FICA?

Certain pre-tax deductions can reduce the amount of income subject to FICA taxes. These may include traditional 401(k) contributions, health insurance premiums, and flexible spending accounts. The IRS provides specific guidance on which benefits qualify.

Need Help With Payroll? Let CMP Handle It

Managing payroll may seem straightforward at first, but it quickly becomes a time-consuming process filled with details, deadlines, and legal obligations. From calculating deductions to staying compliant with federal and Utah state laws, even small mistakes can lead to costly consequences.

At CMP, we help business owners take the stress out of payroll. Our accounting and payroll services are designed to simplify the process, ensure compliance, and free up your time so you can focus on growing your business.

If you’re a business owner in Logan, Salt Lake, or St. George, we’re here to simplify your payroll and ensure compliance every step of the way. Reach out today to learn how our team can support your payroll needs with accuracy and care.

Let's Talk: Schedule A Consultation Today.

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