A paycheck stub looks like it was designed to be ignored: a dense grid of abbreviations, percentages, and numbers that don't obviously add up to anything. Most people glance at the one number that matters to them (what actually hit their bank account) and skip the rest. That's a missed opportunity: your pay stub is one of the most useful documents you get every month, once you know how to read it.
The core equation: gross pay minus deductions equals net pay
Every paycheck follows the same basic structure:
Gross pay − taxes − deductions = net pay (take-home pay)
- Gross pay is your total earnings before anything is taken out: your salary divided into that pay period, or your hours worked times your hourly rate, plus any overtime or bonus.
- Net pay is what actually lands in your bank account: gross pay after every tax and deduction has been subtracted.
- Everything in between is a specific tax or deduction, each doing a different job.
Your salary is not your paycheck
When people say "I make $65,000," they're describing gross pay, the number before taxes and deductions. Your actual take-home pay, the amount you can budget with, is always lower, often by a meaningful margin. Budgeting off your salary instead of your net pay is one of the most common early-career money mistakes.
Taxes: the first layer of deductions
Taxes come off first, calculated on your gross pay (minus any pre-tax deductions, covered next). The main categories on a U.S. pay stub:
- Federal income tax: withheld based on the information you provided on your Form W-4, an IRS form that tells your employer how much to withhold based on your filing status, other income, and dependents.
- State income tax: withheld similarly, if your state has an income tax (a handful of U.S. states don't).
- Social Security tax: 6.2% of your wages, up to an annual wage cap that adjusts periodically. This funds the Social Security program.
- Medicare tax: 1.45% of your wages, with no annual cap, funding the Medicare program. Together, Social Security and Medicare taxes are often labeled "FICA" on a pay stub, short for the Federal Insurance Contributions Act that created them.
Federal and state income tax withholding are estimates, not final bills. They're your employer's best guess at what you'll actually owe based on your W-4, reconciled against your real tax liability when you file your annual tax return. FICA taxes, by contrast, are a fixed percentage with no year-end reconciliation.
Pre-tax deductions: lowering your taxable income
A pre-tax deduction is subtracted from your gross pay before income taxes are calculated, which means it lowers the amount of income the government taxes you on. Common examples:
- Traditional 401(k) or 403(b) contributions: retirement savings deducted before tax (see Roth vs. traditional IRA for how this compares to Roth accounts, which work differently).
- Traditional health insurance premiums: your share of the cost of employer-sponsored health coverage.
- HSA contributions: Health Savings Account contributions, available if you're enrolled in a qualifying high-deductible health plan.
- FSA contributions: Flexible Spending Account contributions for healthcare or dependent care costs, generally with a "use it or lose it" rule each year.
Tip
Example: if your gross pay is $4,000 for a pay period and you contribute $400 pre-tax to a 401(k) and $150 pre-tax to health insurance, federal and state income tax are calculated on $3,450, not $4,000. Social Security and Medicare tax, by contrast, are still generally calculated on the amount before the 401(k) deduction, since 401(k) contributions don't reduce FICA wages the way they reduce income tax wages.
Post-tax deductions: taken out, but not tax-advantaged the same way
A post-tax deduction is subtracted after taxes are already calculated, so it doesn't lower your taxable income for the current year. Common examples:
- Roth 401(k) contributions: retirement savings taxed now, generally tax-free in retirement.
- Post-tax insurance premiums: some supplemental insurance policies (like certain life or disability policies) are only offered post-tax.
- Wage garnishments: court-ordered deductions, if applicable.
- Union dues, charitable pledges, or other voluntary post-tax deductions.
A full worked example
Here's a sample pay stub for someone earning $60,000 a year, paid biweekly (26 pay periods a year), contributing 6% to a traditional 401(k) and paying $120 biweekly for health insurance:
| Line item | Amount |
|---|---|
| Gross pay (biweekly) | $2,307.69 |
| Pre-tax: 401(k) contribution (6%) | −$138.46 |
| Pre-tax: health insurance premium | −$120.00 |
| Taxable wages (income tax) | $2,049.23 |
| Federal income tax withheld | −$185.00 |
| State income tax withheld | −$65.00 |
| Social Security tax (6.2% of gross) | −$143.08 |
| Medicare tax (1.45% of gross) | −$33.46 |
| Net pay (take-home) | $1,760.19 |
Notice that Social Security and Medicare are calculated on the full $2,307.69 gross pay, while federal and state income tax are calculated on the lower $2,049.23 after the pre-tax deductions. This is exactly the mechanism described above, and it's why two employees with the same gross pay can have noticeably different net pay based only on their benefit elections.
Year-to-date (YTD) totals
Most pay stubs also show a "year-to-date" column next to each line item, tracking the running total for the calendar year. This is useful for a few practical reasons:
- Verifying your Social Security tax stops correctly once you hit the annual wage cap, if your income is high enough.
- Tracking progress toward retirement account contribution limits, so you don't accidentally overcontribute.
- Reconciling against your annual tax documents (like a W-2) at year-end: the YTD totals on your final pay stub of the year should closely match the totals on your W-2.
Other common line items
- Employer contributions: some stubs show employer-paid amounts, like a 401(k) match or the employer's share of health insurance, that don't affect your net pay but are worth knowing about since they're part of your total compensation.
- PTO or sick leave balances: accrued and used paid time off, often tracked in hours.
- Imputed income: the taxable value of certain non-cash benefits (like employer-paid life insurance above a certain amount), added to your taxable wages even though you never receive it as cash.
Why this actually matters for your budget and your automation
Your budget should always be built around net pay, not gross pay. See how to budget for the underlying method. And once you understand exactly how your paycheck is structured, it becomes much easier to set up automated transfers correctly, since you'll know precisely what's already being handled before the money reaches your checking account (retirement contributions, insurance) versus what you still need to route manually to savings and investing.
Reading your pay stub carefully once a year, ideally right after any raise, benefit election change, or job change, is also the easiest way to catch payroll errors (a wrong W-4 filing status, a missed benefit enrollment, or an incorrect deduction amount) before they compound over dozens of pay periods.
Key takeaway
Your paycheck is a sequence of subtractions from a starting point, and every line does a specific job: taxes fund public programs, pre-tax deductions lower what you're taxed on, and post-tax deductions come out of what's left. Understanding each layer turns a confusing stub into a genuinely useful financial document.
Put it on autopilot
Once you know exactly what's coming out of your paycheck and why, the natural next step is making sure the rest (savings, sinking funds, and investing) happens automatically too. See how to automate your entire financial life.
Frequently asked questions
Why is my take-home pay so much lower than my salary?
Your salary is your gross pay before anything is taken out. Taxes (federal, state, and FICA), plus any pre-tax deductions like a 401(k) contribution or health insurance premium, are all subtracted before you receive your net pay. It's common for take-home pay to land 20-35% below gross pay once all of this is accounted for, though the exact gap depends heavily on your income level, state, and benefit elections.
What's the difference between a pre-tax and a post-tax deduction?
A pre-tax deduction, like a traditional 401(k) contribution or a traditional health insurance premium, is subtracted from your pay before taxes are calculated, which lowers your taxable income. A post-tax deduction, like a Roth 401(k) contribution, is taken out after taxes are already calculated, so it doesn't reduce your taxable income now but generally isn't taxed again later.
Should I be worried if my paycheck withholding changes month to month?
Small changes are normal. They often reflect a bonus, overtime, a change in your benefit elections during open enrollment, or hitting the annual Social Security wage cap partway through the year. A large, unexplained change is worth asking your payroll or HR department about directly, since it could also signal a data entry error in your W-4 or benefit elections.