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2026 · Eight causes · Costed for your paycheck

Why Is My Paycheck Different This Time? (2026)

Nothing changed and the paycheck did. Usually one of eight things happened, and each leaves a fingerprint on the stub. The finder above costs every cause for your salary so you can match the fingerprint to the amount.

Your paycheck before the change: $2,262.23 net on $2,884.62 gross. Each cause below shows what it would do on its own; adjust the amounts to match your situation.

Possible causeChange in netWhy
Health premium went up $40 per paycheck (§125, pre-tax)$24.94A pre-tax premium costs less than its face value because it lowers taxable and FICA wages.
401(k) contribution rose by 2% of pay$40.39Lowers federal and state taxable wages, not FICA. Auto-escalation each January is the usual cause.
Extra withholding of $50 on W-4 step 4(c)$50.00Dollar for dollar. Check the W-4 on file if you never asked for it.
Raise of 3%+$53.95Taxed at the marginal rate: only 78%-ish of it arrives.
Crossed the Social Security wage base+$178.85Above $184,500 of year-to-date wages the 6.2% stops; in January it starts again.
A $1,000 bonus in the same paycheck (aggregate method)+$700.42Added to the regular pay and annualised, the bonus is withheld at a higher rate than the flat 22%.
Filing status on the W-4 changed from single to married+$116.54The married table has wider brackets, so withholding drops. Correct only if you file jointly.
Box 2(c) ticked (two jobs)$180.65Halves the brackets so that each job is withheld as if it earned half the household income.

Figures on this page

What this calculator does not do

    Your stub says something else? Report a discrepancy: it is checked against the source and answered on the corrections page.

    January: new tables, new limits, new premiums

    The first paycheck of the year changes for almost everyone. The IRS tables are indexed, so federal withholding on the same salary drops slightly — the standard deduction went from $15,750 to $16,100 single — and state tables move too. The Social Security cap resets, so anyone who stopped paying it in the autumn starts again: on $250,000 the biweekly paycheck falls from $7,502.73 to $6,906.58. Health premiums change with the plan year at open enrolment, usually upward. 401(k) auto-escalation adds a percentage point on the anniversary or in January. And state disability and paid-leave rates change on January 1 in California, New York, Washington and others.

    The Social Security cap, both directions

    Social Security stops when year-to-date wages pass $184,500, and the paycheck grows by 6.2% of gross — $596.15 on $250,000 biweekly — from that paycheck to December, then shrinks again in January. A bonus paid early in the year brings the cap forward. Someone who changed jobs mid-year hits it later or not at all with the new employer, since each employer counts its own wages, and the excess is refunded on the return. Above $200,000 of year-to-date wages the 0.9% Additional Medicare Tax starts, a smaller change in the other direction.

    Benefits and deductions

    A premium increase at renewal, a plan change at open enrolment, a dependent added after a birth or a marriage, an FSA election starting, a 401(k) percentage rising by auto-escalation, a Roth election replacing a traditional one (same amount, more tax, smaller net), a garnishment or child support order starting, a loan repayment or a union dues change. Each appears on its own line and the year-to-date column shows when it began. A §125 deduction also changes the FICA lines, so a new health premium reduces Social Security and Medicare by 7.65% of itself — a fingerprint that distinguishes it from an after-tax deduction of the same size. The pre-tax deductions calculator shows the exact cost of each kind.

    The W-4 and the state form

    A new W-4 changes federal withholding from the next payroll: box 2(c) checked or unchecked, dependents added or removed, extra on 4(c), a filing status change after a marriage or divorce. Payroll systems occasionally reset a W-4 during a migration between providers, and an employer that received a lock-in letter must withhold at single with no adjustments. The state form changes the state line the same way. If federal withholding changed and nothing else did, the W-4 on file is the first thing to ask for; the walkthrough reproduces the figure from any W-4.

    The pay itself: hours, overtime, bonus, retro

    For hourly employees the paycheck varies with the hours, and a semi-monthly period varies with the calendar even at fixed hours; overtime is paid when the workweek ends, sometimes a period late. A bonus or commission in the paycheck raises it and is withheld at either the flat rate or the aggregate method, which annualises the combined paycheck and takes more than the flat 22%. A retroactive raise arrives as a lump for the back periods. A raise itself is taxed at the margin, so a 3% raise on $75,000 in California adds only $53.95 to a biweekly paycheck — 62.3% of the gross raise.

    A worked example: $52,000 in Colorado, paid monthly

    Take $52,000 a year in Colorado, paid monthly (12 paychecks), single, standard W-4, no pre-tax deductions. The gross per paycheck is $4,333.33. Federal income tax withholding, from the 2026 Publication 15-T percentage method, takes $338.33. Social Security takes 6.2% of gross, $268.67, and Medicare 1.45%, $62.83. Colorado withholds $131.63 under its flat rate and deductions. The net deposit is $3,531.87, 81.5% of gross; over the year that is $42,382 from $52,000, an effective rate of 18.5% on all taxes together. Every line is reproducible from the documents on the sources page, and the table below lists them in the order they appear on a stub.

    Two things on that stub are not obvious from the totals. First, the federal line is withholding, not tax: the tables annualise this paycheck as if all 12 were identical, and the year's actual tax, $4,060, differs from the $4,060 withheld by $0, which becomes a bill in April. Second, Social Security and Medicare are the same fraction of every paycheck of the year, because the salary is under the wage base, and no form can change them; only Section 125 deductions reduce their base. The reading guide walks each line and names what it should equal.

    LineThis paycheckPer yearShare of gross
    Gross pay$4,333.33$52,000100%
    Federal income tax−$338.33−$4,0607.8%
    Social Security−$268.67−$3,2246.2%
    Medicare−$62.83−$7541.4%
    Colorado income tax−$131.63−$1,5803.0%
    Net pay$3,531.87$42,38281.5%

    Nearby salaries: what $32,000 to $87,000 leave in Colorado

    A raise or a job offer is rarely at the round number on this page, so here is the ladder around it: the same monthly paycheck at 6 salaries from $32,000 to $87,000, single, standard W-4, no deductions. The effective rate climbs from 15.0% to 23.1% across the range because federal income tax is progressive while FICA is flat; each extra $10,000 of salary leaves less than the last, and the pay raise calculator prices any step exactly. The salary after tax pages carry the full range, one page per amount.

    Reading the ladder the other way answers the interview question: to take home $10,000 more a year in Colorado takes a raise of roughly $13,002 in gross at this level, because the new dollars are taxed at the marginal rate rather than the average. The state column grows in a straight line, since Colorado charges one rate; the FICA column grows in a straight line until the wage base. The gross-up calculator runs the reverse computation for any net.

    SalaryGross per monthFederalFICAState + localNetEffective rate
    $32,000$2,666.67−$138.33−$204.00−$58.30$2,266.0415.0%
    $42,000$3,500.00−$238.33−$267.75−$94.97$2,898.9517.2%
    $52,000 (this page)$4,333.33−$338.33−$331.50−$131.63$3,531.8718.5%
    $62,000$5,166.67−$438.33−$395.25−$168.30$4,164.7919.4%
    $72,000$6,000.00−$584.17−$459.00−$204.97$4,751.8620.8%
    $87,000$7,250.00−$859.17−$554.63−$259.97$5,576.2323.1%

    The same paycheck under each filing status

    Filing status is the one W-4 line everyone fills in, and it moves the federal line more than most people expect. On $52,000 in Colorado, paid monthly, a single filer is withheld $338.33 per paycheck; married filing jointly (one income) $165.00, because the joint table doubles the standard deduction to $32,200 and widens every bracket; head of household $249.00, with its $24,150 deduction and its own brackets. Married filing separately uses the single table. Colorado's own deductions and brackets are the same for joint filers, which is why the state column moves too. Picking «married» with two incomes and skipping step 2 is the commonest cause of an April bill; the W-4 guide covers the choice.

    The last column shows why the status matters beyond the paycheck: the year's federal income tax on $52,000 is $4,060 single and $1,980 married filing jointly on one income, a difference of $2,080 that the W-4 status either delivers through the year or holds back for a refund. Head of household is the status most often missed by single parents, who leave $1,072 a year on the single table. FICA is identical in every row, since it has no status.

    StatusStandard deductionFederal per paycheckState per paycheckNet per paycheckFederal tax for the year
    Single (this page)$16,100−$338.33−$131.63$3,531.87$4,060
    Married filing jointly$32,200−$165.00−$72.60$3,764.23$1,980
    Married filing separately$16,100−$338.33−$131.63$3,531.87$4,060
    Head of household$24,150−$249.00−$131.63$3,621.20$2,988

    The whole year on $52,000: withholding, tax due, and the settlement

    12 paychecks of $4,333.33 withhold $4,060 of federal income tax over 2026. The tax actually due on the return, with the $16,100 standard deduction and no credits, is $4,060, so the year ends with about $0 owed — the gap between the withholding tables' approximation and the exact computation. The marginal rate on the last dollar is 12%; the effective rate on all taxes together is 18.5%. Social Security applies to every paycheck of the year, because $52,000 is under the $184,500 wage base. The 2026 deductions for overtime premium and tips apply at filing to anyone with qualifying pay; they do not change these paychecks. Colorado takes $1,580 for the year, 3.0% of salary.

    Refund or bill: what the year settles

    Withholding is a prepayment; the return computes the tax and returns or collects the difference. On $52,000 with these settings the year withholds $4,060 against $4,060 due, so the settlement is a bill of about $0. A refund is money lent to the Treasury at no interest for up to sixteen months; a bill is fine up to a point and penalised beyond it. The point is the safe harbour: withholding of at least 90% of this year's tax ($3,654 here) or 100% of last year's (110% above $150,000 of income) avoids the underpayment penalty, which is interest on each quarter's shortfall. These paychecks clear the 90% harbour on their own.

    What makes the settlement move: credits the W-4 does not carry (the earned income credit, education credits, the 2026 overtime and tip deductions), which enlarge the refund; a second income, other income, or too many dependents on the form, which produce the bill; a bonus withheld at the flat 22% when the marginal rate is 12%, which over-withholds at this salary; and a change of job or a partial year, which annualises each paycheck wrongly. The W-4 fixer sets the lines that bring the settlement to zero, or to a chosen refund.

    What deductions do to this paycheck

    Deductions are where the same salary produces different paychecks. A 6% traditional 401(k) contribution — $260.00 per paycheck on $52,000, well under the $24,500 annual limit — reduces federal and state taxable wages but not FICA wages, so it costs $217.36 of take-home rather than its face value. A $150 Section 125 deduction for health premiums or an HSA reduces every base including FICA, and costs $113.93. A Roth contribution of the same 6% comes out after tax and costs the full amount now in exchange for tax-free withdrawals later. The table gives each case for this paycheck; the pre-tax deductions calculator runs any amount and the 401(k) calculator draws the whole curve.

    The order matters on the stub as well as in the arithmetic. Section 125 items come off first and reduce the FICA wages line, which is why a health premium lowers the Social Security and Medicare figures by 7.65% of itself; the 401(k) comes off next and reduces federal taxable wages only. Both appear in the W-2: box 1 (federal wages) is gross minus both, boxes 3 and 5 (Social Security and Medicare wages) are gross minus the Section 125 items alone. An employer match, where there is one, is added on top of the contribution and never touches the paycheck; the compare two jobs tool values it.

    DeductionNet per paycheckChangeTax saved per year
    No deductions$3,531.87
    6% traditional 401(k) ($260.00)$3,314.51−$217.36$512
    $150 health / HSA (§125)$3,417.94−$113.93$433
    Both$3,200.58−$331.29$945
    6% Roth 401(k) (after tax)$3,271.87−$260.00$0 now; tax-free later

    What each W-4 line does to this paycheck

    The federal line is the only tax on the stub that a form can change, and each step of the W-4 moves it by a predictable amount. One qualifying child on step 3 lowers withholding by $183.33 per paycheck — the $2,200 credit spread over 12 paychecks — taking the net to $3,715.20. Checking box 2(c) for a second job raises it by $247.09, because the checkbox table halves the brackets so that each job is withheld as if it earned half the household income. Extra withholding on 4(c) is dollar for dollar. Other income on 4(a) adds the tax on it at the marginal rate; deductions on 4(b) remove it. The table runs each case for $52,000 in Colorado; the W-4 fixer computes the combination that makes the year's withholding equal the year's tax.

    None of these lines changes the tax; they change when it is paid. Claiming a child that is not yours on step 3, or deductions you will not take on 4(b), enlarges every paycheck and produces the same amount plus a penalty in April. The lawful levers are the ones you are entitled to — the children you have, the deductions you will itemise, the second income you must account for — and the fixer applies exactly those. A new W-4 takes effect from the next payroll run after your employer receives it, and the year-to-date withholding already taken is not recomputed.

    W-4Federal per paycheckChangeNet per paycheck
    Standard W-4−$338.33+$0.00$3,531.87
    One qualifying child (step 3: $2,200)−$155.00−$183.33$3,715.20
    Two children (step 3: $4,400)−$0.00−$338.33$3,870.20
    Box 2(c) checked (two jobs)−$585.42+$247.09$3,284.78
    Extra $50 on step 4(c)−$388.33+$50.00$3,481.87
    $5,000 other income on step 4(a)−$388.33+$50.00$3,481.87
    $8,000 deductions above the standard on step 4(b)−$258.33−$80.00$3,611.87

    $52,000 in Colorado against nine other states

    Federal tax and FICA are the same everywhere; the state line is what moves. On $52,000 paid monthly, the nine states with no wage tax leave $3,663.50 per paycheck; California leaves $3,566.87, $96.63 less, or $1,160 over the year. Flat-rate states sit in between and their rate is the whole story; bracket states depend on the salary. Prices move more than taxes between most of these states, and the state pages carry the BEA price index beside the take-home; the state ranking sorts all 51 for any salary.

    Two cautions before reading the table as a moving guide. The state taxes wages where the work is done, with the resident state taxing everything and crediting the work state, so a remote job does not change the column unless you change where you live — and five states apply a «convenience of the employer» rule that keeps taxing remote work done elsewhere. And the no-tax states collect the difference elsewhere: property tax in Texas and New Hampshire, sales tax in Tennessee and Washington. The no-income-tax guide and the local taxes guide cover both.

    StateSystemState per paycheckNet per paycheckState tax per year
    Colorado (this page)Flat−$131.63$3,531.87$1,580
    TexasNone−$0.00$3,663.50$0
    FloridaNone−$0.00$3,663.50$0
    WashingtonNone−$0.00$3,663.50$0
    CaliforniaBrackets−$96.63$3,566.87$1,160
    New YorkBrackets−$184.25$3,479.25$2,211
    IllinoisFlat−$202.43$3,461.07$2,429
    PennsylvaniaFlat−$133.03$3,530.47$1,596
    OhioBrackets−$50.99$3,612.51$612
    GeorgiaFlat−$166.33$3,497.17$1,996
    North CarolinaFlat−$130.51$3,532.99$1,566

    A raise on $52,000: what arrives

    A raise is taxed at the margin, so what reaches the account is the raise minus the marginal federal rate, FICA and the state's marginal rate on the new dollars only. A 3% raise on $52,000 in Colorado adds $130.00 of gross to a monthly paycheck and $98.73 of net, 75.9% of it; against 3% inflation it is a real raise of about 0.0%. Nothing about the raise changes the tax on the salary below it — the «pushed into a higher bracket» fear describes arithmetic that does not exist in a progressive system. The table runs three sizes; the pay raise calculator runs any, with the inflation figure you enter.

    RaiseGross per paycheckNet per paycheckKeptNet per year
    3% ($53,560)$130.00$98.7375.9%$1,185
    5% ($54,600)$216.67$164.5575.9%$1,975
    10% ($57,200)$433.34$329.1275.9%$3,949

    A bonus on top of $52,000

    A bonus paid separately is withheld at the flat 22% federal rate plus FICA and state: a $1,000 bonus leaves $699.83 and a $5,000 bonus $3,499.16 in Colorado. Paid inside a regular paycheck under the aggregate method, the same bonuses are withheld $120.00 and $979.17 federally instead of $220.00 and $1,100.00, because the combined paycheck is annualised as if it recurred. The tax actually owed is the marginal rate — 12% at this salary — so the $5,000 bonus is really taxed $600.00 federally and the flat method returns $500.00 at filing. The bonus calculator shows both methods for any amount and state.

    $52,000 on each pay schedule

    The annual figures do not change with the pay schedule — $52,000 in Colorado leaves the same $42,382 whether it arrives 52 times or 12 — because the withholding tables are the annual tables divided by the number of periods. What changes is the slice: a semi-monthly paycheck is 8.3% larger than a biweekly one, a monthly one more than double a biweekly one, and a weekly one half. Budgets are built from the slice, which is why the pay periods guide and the biweekly vs semi-monthly guide matter more than the small difference in withholding precision between them.

    Employers choose the schedule, within the minimum their state sets, and the choice follows the workforce: hourly staff are usually paid weekly or biweekly because overtime is computed by the workweek, and salaried staff semi-monthly or monthly because their pay does not vary. A change of schedule re-spreads every per-paycheck deduction — a monthly premium divided by 2 instead of 2.1667 — and usually leaves a one-time gap between the last paycheck on the old schedule and the first on the new. The table gives $52,000 on all four; the frequency pages carry the calendar for each.

    SchedulePaychecksGrossFederalNetNet per year
    Weekly52$1,000.00−$78.08$815.04$42,382
    Every two weeks26$2,000.00−$156.15$1,630.10$42,383
    Twice a month24$2,166.67−$169.17$1,765.93$42,382
    Monthly (this page)12$4,333.33−$338.33$3,531.87$42,382

    When it is an error

    A state changed without a move (a remote employee re-coded to the office state). Social Security withheld past the cap. A §125 deduction set up as after-tax. A W-4 reset. Overtime at the base rate without the shift differential. Hours missing. The stub checker on the accuracy guide compares each line with the computed figure and names the largest gap. Errors are corrected in the next payroll or by an off-cycle payment; over-withheld tax that payroll will not refund is recovered on the return.

    The three taxes on a paycheck, and why they behave differently

    Federal income tax is progressive and starts from zero: the first $16,100 a single filer earns in 2026 is untaxed because that is the standard deduction, and the rate then climbs through seven brackets from 10% to 37%. It is the only line your W-4 changes. FICA is flat from the first dollar — 6.2% for Social Security up to $184,500 of wages and 1.45% for Medicare without limit — and no form changes it. State income tax is whatever your state decided: nothing in 9 states, one flat rate in 13, brackets in the other 29, and 11 states let a city or county add a line of their own.

    On the $2,307.69 biweekly example above: $193.08 of federal withholding, $176.54 of FICA and $0.00 of Texas tax. Keeping them on separate lines is the point: a 401(k) contribution moves the first and third but not the second; a raise moves all three at different rates; the Social Security cap moves only the second. A single «taxes» figure hides which lever does what.

    Pre-tax deductions: what each one really costs

    A $250 contribution to a traditional 401(k) does not cost $250 of take-home. It comes out before federal income tax (and before state tax in most states), so at a 12% marginal rate the paycheck falls by about $220.00. What it does not escape is FICA: the IRS is explicit that elective deferrals are wages for Social Security and Medicare, so the saving is the income tax rate, not the income tax rate plus 7.65%. Health premiums, HSA and FSA contributions through a Section 125 plan are the exception and escape FICA too: the same $250 through an HSA costs about $200.88 of take-home.

    After-tax deductions — a Roth 401(k), union dues, garnishments, post-tax life cover — reduce nothing but the deposit, and still belong in the calculation because the deposit is the number that matters. On a $2,307.69 paycheck, the 401(k) calculator draws the cost curve one percent at a time and the pre-tax deductions calculator compares the two kinds side by side.

    What changed in 2026

    The standard deduction is $16,100 single, $32,200 joint and $24,150 head of household; every bracket threshold moved up with inflation; the Social Security wage base is $184,500; the 401(k) elective limit is $24,500. Each is read from the document that sets it — IRS Revenue Procedure 2025-32, the SSA's contribution and benefit base, IRS Notice 2025-67 — and listed with its source under the calculator.

    The bigger change is the set of new federal deductions: qualified overtime premium pay up to $12,500 ($25,000 joint), reported tips up to $25,000, and $6,000 more for each person aged 65 or over, all phasing out above $150,000 of income. None of them changes what an employer withholds, because Publication 15-T does not know about them; they reduce the tax owed at filing, which is why the calculators on this site show them in the «withholding vs what you owe» box rather than on the paycheck. The what changed in 2026 guide keeps the dated list, including state changes.

    Common mistakes

    Assuming a raise should show up in full. It is taxed at the margin. Missing the January reset of the Social Security cap. Not reading the year-to-date column, which dates every change.

    Reading the flat 22% on a bonus as the tax on it. It is withholding; the tax is your marginal rate. Budgeting from the wrong paycheck: biweekly and semi-monthly differ by about 7.7%. Claiming the same child on two W-4s, which under-withholds the household by the credit. Assuming a raise can push you into a bracket that leaves you worse off — in a progressive system it cannot. Forgetting the Social Security cap: above $184,500 the later paychecks are larger, and a budget built on January's paycheck is too tight for December's.

    Questions

    Why did my paycheck go down without a raise?
    Most often: January (Social Security cap reset, new premiums, 401(k) auto-escalation), a benefits change, a W-4 change, or a garnishment. The finder above costs each for your salary.
    Why did my paycheck go up?
    Usually the Social Security cap — wages past $184,500 stop paying 6.2% — or new January tax tables, a dependent added on the W-4, or a raise.
    Why is my paycheck different every month?
    On a semi-monthly schedule with hourly pay, the number of working days per half-month varies from 10 to 12; overtime is also paid when the workweek ends.
    Why was less tax taken out this paycheck?
    New year tables, a W-4 change, a pre-tax deduction starting, or a prorated paycheck that annualises to a small salary.

    Sources

    An estimate for planning, not tax or payroll advice.

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