PaystubFreeNo signupEstimates only
Turn a few paycheck numbers into a labeled stub: pre-tax vs post-tax, taxable wages, FICA, YTD, and the employer match you do not see deposited.
Last updated 3 October 2026
Estimates only — not tax, payroll, or financial advice. This is a simplified educational calculator (2026-ish federal brackets + standard deduction, employee FICA, optional flat state tax). It is not IRS Publication 15-T withholding, a substitute for your W-4, or a tax return. Real paystubs vary with credits, benefits, local taxes, additional Medicare tax, and your employer’s payroll system. Confirm numbers with a qualified tax or payroll professional.
A single paycheck of $2,500 produces at least four different wage figures, and a real stub prints most of them in a column with no explanation of why they differ. Gross is $2,500.00. Federal taxable wages might be $2,350.00. Social Security wages might be $2,500.00 while the Medicare wages beside them are also $2,500.00 and the net deposit is $2,092.60. None of those numbers is a mistake. Each one is a different legal definition of the word “wages”, each is fixed by a different instruction, and each rolls up into a different box of the W-2 you will get in January.
This page is organised around those wage figures rather than around the deduction lines, because the deductions are easy and the wage bases are where stubs actually confuse people. Everything below is anchored to the IRS General Instructions for Forms W-2 and W-3 for 2026 and to Publication 15, and where the calculator above departs from them, it is said plainly.
The only figure on the stub with no asterisk. It is what you earned before anything was taken out, and every other number on the page is derived from it. If this figure is wrong, stop reading and take it up with payroll, because nothing downstream can be right.
One thing worth checking on a real stub: gross for the period should equal your rate multiplied by the hours or days the period covers, and the Fair Labor Standards Act requires your employer to be keeping the records that prove it — specifically “Hours worked each day”, “Total hours worked each workweek”, “Regular hourly pay rate” and “Total daily or weekly straight-time earnings”. Those records exist whether or not they are printed on your stub.
This is gross minus the deductions that are allowed to come out before federal income tax is computed. The IRS defines the annual version of it precisely, in the instruction for box 1 of the W-2: “Show the total taxable wages, tips, and other compensation that you paid to your employee during the year. However, do not include elective deferrals (such as employee contributions to a section 401(k) or 403(b) plan)…”
So a traditional 401(k) deferral is carved out of box 1 by name. On a $2,500 check with $150 deferred, federal taxable wages fall to $2,350.00 and the estimated federal income tax falls from $216.15 to $198.15 — $18.00 saved, which is 12% of $150, because 12% is the marginal bracket this salary sits in. That ratio, not the 22% people expect, is the real return on a pre-tax deferral at this income; the 401(k) paycheck impact page works the cost per dollar out in detail.
The same box 1 instruction also lists what stays in, and two entries on it surprise people: “Taxable benefits from a section 125 (cafeteria) plan if the employee chooses cash”, and “Taxable cost of group-term life insurance in excess of $50,000”. The second is why some stubs carry a small imputed-income line for a benefit no money was ever paid for. It increases your taxable wages without increasing your gross pay, and the tax on it is withheld from real money.
Here is the line that catches almost everyone, stated by the IRS in a single sentence in the box 3 instruction: “Report in box 3 elective deferrals to certain qualified cash or deferred compensation arrangements and to retirement plans described in box 12 (codes D, E, F, G, and S) even though the deferrals are not includible in box 1.”
Your 401(k) leaves box 1 and stays in box 3. Publication 15’s section 15 table says the same thing from the employer side: elective deferrals are generally exempt from income tax withholding “but see section 402(g) for limitation”, and are Taxable for Social Security, Medicare and FUTA. That is why the Social Security line on the stub above does not move when you enter a 401(k) amount: $155.00 before, $155.00 after. Deferring income does not defer FICA, it only defers income tax, and the Social Security credit you earn is based on box 3, so the deferral does not reduce your eventual benefit either.
What does come out of box 3, sometimes, is a cafeteria plan benefit under section 125 — health premiums, typically. Publication 15 is careful with the wording: those benefits “may qualify” for exclusion from Social Security, Medicare and FUTA. May, not do. Which of your pre-tax lines qualify depends on how your employer’s plan is written, and it is the single most common reason a stub’s Social Security line is not exactly 6.2% of gross.
Box 3 also has a ceiling, and the 2026 instruction states it as a hard rule: “The total of boxes 3 and 7 cannot exceed $184,500 (2026 maximum social security wage base).” Once your year-to-date Social Security wages reach $184,500, the 6.2% stops for the rest of the calendar year. It does not taper and it is not averaged across the year; it switches off mid-paycheck on the day you cross.
Box 5 starts from the same base as box 3 and then diverges in exactly one way: it has no ceiling. The IRS instructions make the point with their own worked example, which is worth quoting in full because it settles the question faster than any explanation: “You paid your employee $199,750 in wages. Enter in box 3 (social security wages) 184500.00, but enter in box 5 (Medicare wages and tips) 199750.00. There is no limit on the amount reported in box 5. If the amount of wages paid was $184,500 or less, the amounts entered in boxes 3 and 5 will be the same.”
That last sentence is why most people never notice. Below the wage base, boxes 3 and 5 are identical and the difference is invisible. Above it, they separate permanently.
A second rate arrives on top. Topic no. 560 sets the Additional Medicare Tax at 0.9%, and the employer must start withholding it once wages for the year exceed $200,000, “without regard to the employee’s filing status”. Your own thresholds are different — $250,000 married filing jointly, $125,000 married filing separately, $200,000 otherwise — and are settled on your return, so a married couple can have it withheld and get it back, or not have it withheld and owe it.
The employer owes its own Social Security and Medicare on the same wages, at the same rates: 6.2% to the same $184,500 base, and 1.45% with no base. On a $2,500 paycheck that is $155.00 plus $36.25, or $191.25, paid on top of your gross and never deducted from it. Over a year on a $65,000 salary it comes to $4,972.50. It is the clearest single answer to “what does my employment actually cost”, and it is the figure that disappears if you move to 1099 contracting, where you pay both halves yourself.
The match is not quite symmetric, and the asymmetry is in one place. The box 6 instruction reads: “Enter the total employee Medicare tax (including any Additional Medicare Tax) withheld. Do not include your share.” The 0.9% Additional Medicare Tax has no employer match at all. Below $200,000 of annual wages the two Medicare lines on the sample stub are equal to the cent. Above it they separate: on a single paycheck of $250,000 the employee Medicare line is $4,075.00 against the employer’s $3,625.00, and the $450.00 difference is the 0.9% that only one side pays.
Every figure discussed so far is a per-period figure, and per-period figures cannot see a ceiling. The YTD column can, which is what it is for. Two specific uses:
The calculator above uses your YTD figure to work out where in the year this cheque falls, so Social Security stops at the wage base and Additional Medicare Tax starts on the cheque where each actually happens. Enter a $10,000 cheque with $180,000 behind it and the Social Security wages row reads $4,500.00, the only part of the $184,500 base still unused, and the 6.2% row reads $279.00. Until 3 October 2026 the figure was collected and ignored, every cheque was priced as the first of the year, and that row read $620.00 — an overstatement of $341.00 on one cheque, and the largest error this page has had.
It will, and that is deliberate. This section used to list defects found by running the tool against the sources rather than reading its description. As of 3 October 2026 they are all fixed, and what is left is one behaviour that looks like a fault and is not.
Two of the three boxes that take money out before tax are now capped at what the check can actually carry. An over-large 401(k) figure is held to the $24,500 elective deferral limit and to the cash left once FICA is paid, so the $2,000 check with $1,800 deferred reads $360.85 where it used to read −$453.00. The other pre-tax benefits box is held to the same cash bound. Both say on screen what they applied instead of what you typed, and neither can push the deposit below zero.
The post-tax box is not capped, and this is the behaviour worth explaining. Enter $3,000 of post-tax deductions against a $2,000 check and the deposit reads −$1,309.15. There is no payroll rule to copy here: a 401(k) has a legal limit and a cafeteria plan cannot take cash that does not exist, but nothing says what happens when you tell a calculator your union dues, garnishment and loan repayment add up to more than your wages. So the stub subtracts what you entered and tells you, on screen, that the deductions come to more than the check has left after tax.
Capping it would print a deposit of $0.00, which is a worse answer, because it would hide the fact that the figures you entered cannot happen together. A negative number carries information that a floor throws away. What was actually wrong before was not the minus sign, it was that the minus sign arrived with no explanation, so a reader who mistyped a figure reasonably concluded the calculator was broken.
What the other pre-tax benefits box does, now that it reaches the tax. It reduces federal and state income tax, and it does not reduce Social Security or Medicare. That is a real federal category rather than a convenience: Publication 15-B, Table 2-1, lists adoption assistance as “Exempt” under income tax withholding and “Taxable” under Social Security and Medicare. But cafeteria-plan benefits do not share one treatment, and the same table lists accident and health benefits as exempt from both, while Publication 15 adds that benefits under cafeteria plans “may qualify for exclusion from wages for social security, Medicare, and FUTA taxes”. So if what you pay pre-tax is a health premium, this page charges you Social Security and Medicare you would not actually owe. It errs toward more tax, deliberately, because the box cannot know which kind of benefit you have and an estimate that overstates the tax is the safer of the two mistakes. On the state side the direction is settled for the one state known to diverge: Pennsylvania exempts a qualified section 125 benefit “only to the extent they are exempt for federal income tax purposes” while putting 401(k) contributions among amounts “not excludable from Pennsylvania-taxable compensation”, which is the opposite pairing to the one this page applies to the deferral.
Three more limits that are design rather than defect. The state tax line is a flat percentage of wages after the deferral, and no state levies income tax that way — they have brackets, their own standard deductions, their own treatment of retirement contributions. Pennsylvania is the clearest counter-example: it taxes at a flat 3.07% but does not exempt 401(k) deferrals, so a flat-rate model applied after the deferral understates the tax for anyone deferring there. And both the input box and the engine behind it cap the rate at 20%, which is higher than any state's flat rate; anything above that is treated as 20% with no warning on screen. Secondly, the federal income tax line is an annual-liability sketch divided by the pay-period count, not Publication 15-T withholding, so it will not match your stub exactly even when every input is right. It also annualises whatever single paycheck you type: enter one $10,000 check and it reasons about a $260,000 year.
Less than most people assume, and this is the part worth knowing before you argue with payroll.
The Fair Labor Standards Act requires employers to keep a specific list of records for each non-exempt worker, and the Labor Department’s recordkeeping fact sheet enumerates fourteen items. Among them: “Basis on which employee’s wages are paid”, “Regular hourly pay rate”, “Total overtime earnings for the workweek”, “All additions to or deductions from the employee’s wages”, “Total wages paid each pay period”, and “Date of payment and the pay period covered by the payment.” Payroll records must be preserved “for at least three years”, and the underlying time cards and wage-rate tables for two.
But on form, the same fact sheet is explicit: “The Act requires no particular form for the records.” It sets out what must be recorded and kept, and it does not name a requirement that any of it be handed to you as an itemised statement. The duty to give employees a pay statement, and what that statement must show, comes from state law, and it varies: some states require an itemised statement every pay period, some require one only on request, and some have no such requirement at all. This page models none of that, and cannot tell you which state you are in.
So the practical reading is this. Everything on your stub is information your employer is already obliged to possess. If a figure is missing or looks wrong, you are asking for a record that exists, not a favour. But the format in front of you — the abbreviations, the grouping, which totals get printed — is your employer’s payroll vendor’s choice, which is precisely why stub codes differ so wildly between employers and why no decoder, including this one, can name every line on yours.
Part of the PaystubKit tools collection. Calculations run locally in your browser. Estimates only, not tax or payroll advice.
Because “wages” has three legal definitions. Federal taxable wages (W-2 box 1) exclude elective deferrals — the instruction says “do not include elective deferrals (such as employee contributions to a section 401(k) or 403(b) plan)”. Social Security wages (box 3) include them anyway and stop at $184,500 for 2026. Medicare wages (box 5) include them and never stop. The IRS's own example: $199,750 of wages gives box 3 of 184500.00 and box 5 of 199750.00.
No. Publication 15's section 15 table lists elective deferrals as exempt from income tax withholding but Taxable for Social Security, Medicare and FUTA, and the W-2 instructions require them reported in box 3 “even though the deferrals are not includible in box 1”. On a $2,500 check, deferring $150 moves federal income tax from $216.15 to $198.15 and leaves Social Security at $155.00 either way.
The 0.9% Additional Medicare Tax. Your employer must start withholding it once your wages for the year exceed $200,000, regardless of filing status, and there is no employer match — box 6 says to include it in the employee's tax but “Do not include your share”. On a single $250,000 payment the employee Medicare line is $4,075.00 against the employer's $3,625.00. Your own threshold ($250,000 married filing jointly, $125,000 married filing separately, $200,000 otherwise) is settled on your return.
6.2% Social Security to the same $184,500 base, plus 1.45% Medicare with no base. On a $2,500 paycheck that is $155.00 plus $36.25, or $191.25, paid on top of your gross and never deducted from it — $4,972.50 a year on a $65,000 salary. The 0.9% Additional Medicare Tax is the exception: the employer does not match that one.
Yes, since 3 October 2026. Enter a $10,000 check with $180,000 of YTD gross and the Social Security wages row reads $4,500.00, the only part of the $184,500 base still unused, and the 6.2% row reads $279.00. Enter $190,000 and both read $0.00, because the base is spent. The same figure starts Additional Medicare Tax, which begins rather than stops: at $195,000 of YTD gross only the $5,000 of this check above $200,000 is charged the extra 0.9%, so $45.00. Before that date the box was collected and ignored, every check was priced as the first of the year, and that row read $620.00.
The Fair Labor Standards Act requires employers to keep fourteen specific records per non-exempt worker, including “All additions to or deductions from the employee's wages” and “Total wages paid each pay period”, preserved for at least three years — but it adds that “The Act requires no particular form for the records” and names no duty to hand them to you as an itemised statement. That duty, where it exists, comes from state law and varies by state. This page does not model state law.