Understanding Your Paycheck: Where Every Dollar Goes

Updated May 31, 2026 · 9 min read

If you have ever compared the salary on your offer letter to the amount that lands in your bank account, you have felt the gap. The number you negotiated is your gross pay. The number you can spend is your net, or take-home, pay. Between the two sits a stack of taxes and deductions that can quietly subtract a large share of each check. This guide walks through every common line on a US paycheck so you can read your pay stub with confidence and understand exactly where each dollar goes.

Gross pay vs. net pay: why the gap is so large

Gross pay is your full earnings for the pay period before anything is taken out. For a salaried worker it is your annual salary divided by the number of pay periods in the year. For an hourly worker it is your hours multiplied by your rate, plus any overtime or bonuses. Net pay is what remains after every required tax and every deduction you have elected is subtracted.

The gap between the two is not a single fee. It is the sum of several separate items, each calculated differently: federal income tax withholding, Social Security and Medicare (together called FICA), state and sometimes local income taxes, and voluntary deductions such as retirement contributions or insurance premiums. Understanding the gap means understanding each piece on its own.

Federal income tax withholding

The largest line for many workers is federal income tax withholding, and it is important to understand what it actually is: not a final tax bill, but a running prepayment toward the income tax you will owe for the year. It is collected a little at a time from each paycheck so you do not face one enormous bill in April.

How much your employer withholds depends mostly on Form W-4, which you fill out when you start a job and can update anytime. On it you report your filing status, whether you hold more than one job, dependents you expect to claim, and any extra amount you want withheld. Your employer feeds those elections into IRS withholding tables to estimate how much to set aside. Claiming more dependents or adjustments generally lowers withholding; requesting extra withholding or reporting multiple jobs generally raises it.

Because withholding is only an estimate of your eventual liability, the actual rate that applies to your income, the thresholds where it changes, and the standard deduction that reduces your taxable income are all set by federal law and adjusted over time. Rather than memorize figures that change, use the income tax calculator, which reflects the current federal numbers. The key idea is that the federal income tax line on your stub is a forecast, and your W-4 is how you tune it.

FICA: Social Security and Medicare

FICA stands for the Federal Insurance Contributions Act, and it covers two separate payroll taxes that fund two specific programs:

Social Security funds retirement, disability, and survivor benefits. You are, in effect, paying into a system that will pay benefits back to you and your family later in life.
Medicare funds health coverage primarily for people age 65 and older and for certain younger people with disabilities.

Unlike federal income tax, FICA is not adjustable through a form. It is a flat payroll tax applied to your earnings, and your employer pays a matching share on your behalf that never appears on your stub. The exact percentages, and the annual wage base that caps the Social Security portion above a certain level of earnings, are set each year by the federal government and the Social Security Administration. Those current values are built into the paycheck calculator, so you see real dollar amounts rather than figures that shift annually. The takeaway: FICA is a mandatory contribution to programs you may one day draw on, and it comes out of nearly every paycheck.

State and local income taxes

On top of federal taxes, most workers also pay state income tax, and some pay a local income tax as well. This is the line that varies most from one person to the next, because it depends entirely on where you live and work.

Several states have no state income tax at all, so residents there see no state line on their stub.
Many states use a graduated system, where higher earnings are taxed at higher rates, similar in spirit to the federal approach.
Some states use a single flat rate on all taxable income.
A number of cities and counties add a local income tax on top of the state amount.

Because the rules differ so widely, two people earning identical salaries can take home noticeably different amounts simply because of their address. The paycheck calculator lets you choose your state so the estimate reflects local rules.

Pre-tax vs. post-tax deductions

Not everything subtracted from your gross pay is a tax. Many deductions are amounts you have chosen to set aside, and the order in which they are applied matters a great deal for what you owe.

Pre-tax deductions come out of your pay before income tax is calculated, which lowers your taxable income for that check. Common examples include:

Traditional 401(k) or 403(b) retirement contributions.
Contributions to a Health Savings Account (HSA) or a flexible spending account.
Your share of health, dental, and vision insurance premiums, in most employer plans.

Because these come out first, a dollar you direct into a pre-tax 401(k) or HSA is a dollar that is not counted when your income tax withholding is figured. That is why contributing to these accounts can reduce your tax burden in the same period you contribute.

Post-tax deductions, by contrast, are taken after taxes are calculated, so they do not lower your taxable income. A Roth 401(k) contribution, certain insurance products, union dues, and wage garnishments often fall here. The trade-off with a Roth account is that while it does not cut today's taxable income, qualified withdrawals in retirement can be tax-free.

Why your withholding is not your final tax bill

Here is the point that trips up many people. The federal and state income tax taken from your checks all year is an estimate, not a settlement. When you file your tax return, you calculate what you truly owed for the year and compare it to what was withheld:

If your employer withheld more than your final bill, you receive a refund for the difference.
If your employer withheld less than your final bill, you owe the balance due when you file.

A large refund feels like a bonus, but it really means you lent the government money interest-free during the year. Owing a large amount can mean penalties. The goal for most people is to land close to even, and the W-4 is the dial you turn to get there.

A worked example (hypothetical numbers)

Numbers make this concrete. Every figure below is hypothetical and for illustration only — it is not a tax rate, and your real results will differ. Suppose your gross pay is $5,000 a month. A simplified flow from gross to net might look like this:

Gross pay: $5,000 (the starting point).
Pre-tax 401(k): subtract a hypothetical $500. Taxable income for this check is now treated as $4,500, not $5,000.
Pre-tax health premium: subtract a hypothetical $150, further lowering the amount that taxes apply to.
Federal income tax withholding: subtract a hypothetical $600, estimated from your W-4 elections.
FICA (Social Security + Medicare): subtract a hypothetical $330 in payroll taxes.
State income tax: subtract a hypothetical $180 (this would be $0 in a state with no income tax).
Net pay: roughly $3,240 lands in your account.

Notice two things. First, the pre-tax items shrank the base before the tax lines were figured. Second, the total subtracted is the sum of several independent calculations, not one flat percentage. These dollar amounts are invented to show the shape of the math; the paycheck calculator produces estimates using the actual current rules for your pay and state.

Practical tips

A few habits will help you stay in control of your pay:

Read your pay stub each period. It lists gross pay, each tax, each deduction, and net pay, usually with both the current check and a year-to-date total. Spotting an unfamiliar line early can catch payroll mistakes.
Check your withholding once a year and after big life changes — marriage, a new child, a second job, or a move to a new state. The IRS offers a withholding estimator, and you can submit an updated W-4 to your employer at any time.
Understand the real effect of a raise. Because most systems are graduated, only the portion of income above each threshold is taxed at the higher rate. A raise never leaves you with less take-home pay overall, even though it can lift the rate on your top dollars. Run the before-and-after numbers so you know what to expect.
Use pre-tax accounts deliberately. Increasing a traditional 401(k) or HSA contribution lowers your taxable income now, which can soften the bite of each check while building long-term savings.

Key takeaways

Gross pay is what you earn; net pay is what you keep after taxes and deductions.
Federal income tax withholding is a prepayment toward your eventual tax, and your W-4 elections control how much is taken.
FICA funds Social Security and Medicare; it is a mandatory payroll tax, and your employer matches part of it.
State and local income taxes vary widely, and some states have none.
Pre-tax deductions like a traditional 401(k) or HSA lower your taxable income; post-tax deductions do not.
Your withholding is an estimate, so you may get a refund or owe a balance at filing — aiming to break even is usually best.

Ready to see your own numbers? Try the paycheck calculator to estimate your take-home pay by state, or the income tax calculator to dig into your annual federal picture. Both use current, officially sourced figures so the estimates reflect today's rules rather than the hypothetical examples above.

This guide is general educational information, not financial advice. Figures in examples are hypothetical. See our editorial policy for how our content is produced and reviewed.