What happens when you run payroll? A behind-the-scenes walkthrough

You hit "run payroll," and a few days later your employee has money in their account and you're out a bigger chunk than the paycheck itself. In between, a lot happens that most first-time employers never see. Here's what's going on behind that button.

Step 1: gross pay gets calculated

Everything starts with gross pay, the full amount your employee earned before anything comes out. For hourly employees, that's hours worked times their rate, plus overtime if it applies. For salaried employees, it's their annual salary divided by the number of pay periods in the year. This number is the starting point for every calculation that follows, and it's also the number your employee will compare to their much smaller direct deposit and wonder where the rest went.

Step 2: taxes get withheld from the employee's pay

From that gross pay, several things come out before your employee ever sees it:

• Federal income tax, based on the W-4 your employee filled out when they were hired. This form tells you their filing status and any adjustments, and it drives how much gets withheld.
• State income tax, if your state has one, based on a similar state withholding form.
• Social Security, 6.2% of wages up to $184,500 for 2026. Once an employee crosses that wage base for the year, this stops.
• Medicare, 1.45% of all wages with no cap, plus an additional 0.9% on wages over $200,000 for the year. That extra 0.9% is the employee's alone; you don't match it.
• Any benefit deductions the employee has elected, like health insurance premiums or a 401(k) contribution.

What's left after all of that is net pay, the number that lands in their bank account.

Step 3: you owe money too, on top of what you paid them

This is the part that catches new employers off guard. Payroll isn't just moving money from your account to your employee's. You owe your own taxes on top of their wages:

• Matching Social Security, 6.2%, and matching Medicare, 1.45%. This is money you owe in addition to the paycheck, not money withheld from it.
• Federal unemployment tax (FUTA), 6% on the first $7,000 of each employee's wages for the year, usually reduced to 0.6% if your state unemployment taxes are paid on time. That's a maximum of about $42 a year per employee once the credit applies.
• State unemployment tax (SUTA), a rate that varies by state and by your experience as an employer. New employers typically start at a standard rate and it adjusts over time based on your claims history.

A $50,000 salary costs you meaningfully more than $50,000 once these employer-side taxes are added in, before you even factor in benefits or workers' compensation.

Step 4: the money moves

Net pay goes to your employee, usually by direct deposit. The taxes you withheld from their pay and the taxes you owe as the employer don't just sit in your account until tax season. They get deposited with the IRS and your state on a set schedule, monthly or semi-weekly depending on the size of your payroll, well before any quarterly filing is due. This is where payroll software earns its keep: it calculates the right amounts and moves them on the right schedule without you having to track deposit deadlines by hand.

Step 5: the paper trail gets filed

Running payroll generates a stack of federal filings, even if you never see most of them:

• Form 941, filed quarterly, reporting total wages paid and the income and FICA taxes withheld and owed. Due April 30, July 31, October 31, and January 31.
• Form 940, filed annually, reconciling your FUTA tax for the year. Due January 31.
• Form W-2, one per employee, reporting their annual wages and withholdings. Due to employees and the Social Security Administration by January 31.

Your state has its own version of most of these, on its own schedule.

What a pay stub is showing you

Every line on a pay stub maps back to one of these steps: gross pay at the top, each tax and deduction itemized in the middle, net pay at the bottom, often with year-to-date totals alongside each figure. If you've ever looked at a pay stub and wondered why the math doesn't feel intuitive, this is why. It's not one calculation. It's five or six calculations stacked on top of each other, each with its own rate and its own rules.

Why most small business owners don't do this by hand

None of these steps are conceptually complicated on their own. What makes payroll risky to run manually is the volume of small rules and the cost of getting one wrong: a missed deposit deadline, a wrong withholding calculation, a late 941. Payroll software or a payroll service handles the calculations, moves the money on schedule, and files the forms, which is why most employers with even one employee use one instead of building this process themselves.

Getting ready to hire your first employee?

The Hiring Your First Employee Checklist in the Prism resource library walks through the setup steps that come before your first payroll run: getting an EIN, registering for state payroll taxes, and collecting the right paperwork.

Want someone else running the numbers?

A Vibe Check is a free, no-pressure conversation about your business and what payroll support would look like for you. Schedule yours here.

Keep reading

• Hiring your first employee: the setup steps before your first payroll run, from EIN to workers' compensation.
• W-2 vs. 1099: what's the difference and why it matters: the classification question that determines whether any of this applies.

This post is general information, not advice for your specific situation. Payroll tax rates, wage bases, and filing deadlines change from year to year, and your state may have requirements beyond what's covered here. Talk to a tax professional or payroll provider before you run your first payroll.