Are Paycheck Calculators Accurate? Check Yours Line by Line (2026)

What a calculator gets exactly right

Federal income tax withholding is a published procedure with published tables; given the salary, the frequency, the W-4 and the pre-tax deductions, the answer is determined to the cent and a correct calculator matches payroll exactly — $193.08 on $60,000 biweekly, single, no adjustments, in 2026. Social Security and Medicare are percentages of a defined base. State withholding is a published procedure in every state too, and exact when the calculator has the state's current tables and the state form's inputs. The only way to get these wrong is to use last year's tables, which a surprising number of calculators do for months after January, or to skip a W-4 input.

What it can only estimate

Benefits deductions, unless you enter them: a calculator cannot know your health premium or your 401(k) percentage. Local taxes, unless it has your city and applies the resident and non-resident rules. Year-to-date wages, which decide when Social Security stops. State disability and paid-leave contributions, which a few states levy and which many calculators omit. Garnishments. Shift differentials and the regular rate for overtime. A calculator that shows a single «net pay» without asking about any of these is estimating them at zero, and the gap between its figure and the stub is the sum of what it was not told.

Why calculators disagree with each other

Different tax years: the most common cause by far, worth a few dollars per paycheck. Different defaults — one assumes the standard W-4, another assumes box 2(c), a third still assumes «1 allowance» from the pre-2020 form. Different treatment of the state: some apply the state's standard deduction and exemptions, some apply a flat percentage. Rounding: payroll systems round each line to the cent and net is the sum of rounded lines. And some calculators simply carry errors in their state tables, which nobody notices because nobody checks. Two calculators with the same inputs and the same year should agree on federal and FICA to the cent; if they do not, one of them is wrong and it is usually the one with the older tables.

How this site keeps itself honest

Every figure is computed by a deterministic engine from constants that carry the document they came from and the date they were checked; the methodology page lists them. Federal figures come from Rev. Proc. 2025-32, the withholding method from Publication 15-T, each state's rules from its revenue department, and the state pages say whether the 2026 tables were verified against the primary source or compiled pending verification. The AI on each page explains the computed figures and is prevented from producing any number of its own. And every page has a report a discrepancy link: reports are checked against the source, the changelog records what changed, and the Paycheck Reality Index publishes how far real stubs sit from the computed figures once enough have been submitted.

Checking your stub

Enter what the calculator needs — salary, frequency, state, W-4 status, box 2(c), 401(k) and §125 deductions per paycheck — and what the stub says on the five tax lines. The checker computes the expected figures and shows each difference. Social Security should match to the cent if the §125 deductions are right; a gap there is a base error on one side. Federal withholding gaps usually trace to the W-4 on file: dependents, extra withholding, an old form. State gaps trace to the state form. If the stub is right and the calculator is wrong for your state, the report link sends the figures for checking; if the calculator is right and the stub is wrong, payroll owes you a correction.

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.

How the federal withholding is computed

The percentage method of IRS Publication 15-T has four steps. First, the paycheck's taxable wages are multiplied by the number of pay periods to get an annualised figure — $60,000 on this example. Second, that figure is adjusted: the amounts on steps 4(a) and 4(b) of the W-4 are added and subtracted, and if the box in step 2(c) is not checked a fixed $8,600 ($12,900 for joint filers) is subtracted. Third, the adjusted figure is run through the withholding rate table for the filing status, which gives $5,020 for the year for a single filer with no adjustments. Fourth, the step 3 credits are subtracted, the result is divided back into pay periods, and any extra amount from step 4(c) is added.

The tables are the 2026 brackets and the standard deduction rearranged so that the fixed subtraction works out, which is why a person with one job and a clean W-4 is withheld almost exactly their annual tax — $5,020 here, 8.4% of gross, with the last dollar in the 12% bracket. The «Show me the math» diagram under the paycheck calculator walks through the four steps with your own figures.

Withholding is not your tax

Every federal line on a paycheck is an estimate your employer makes on your behalf, following your W-4 and IRS Publication 15-T; the tax itself is settled once a year on your return. On $60,000 in Texas, the year's withholding comes to $5,020 against a projected tax of $5,020: $0 more than needed, which returns as a refund. Neither a refund nor a bill is a mistake by anyone; it means the W-4 on file did not describe the year exactly, and both are fixed on the W-4, not on the paycheck.

The three places the estimate goes wrong most: a second income in the household without the box in step 2(c) checked, so that both employers apply the full $16,100 standard deduction; a bonus withheld at the flat 22% when the marginal rate is something else; and untaxed side income with nothing on step 4(a). From 2026 there is a fourth, in the taxpayer's favour: the deductions for overtime premium pay and tips reduce the tax but not the withholding. The W-4 fixer turns the gap into the exact lines to change.

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.

A worked example: $80,000 in Colorado, paid every two weeks

Take $80,000 a year in Colorado, paid every two weeks (26 paychecks), single, standard W-4, no pre-tax deductions. The gross per paycheck is $3,076.92. Federal income tax withholding, from the 2026 Publication 15-T percentage method, takes $337.31. Social Security takes 6.2% of gross, $190.77, and Medicare 1.45%, $44.62. Colorado withholds $108.14 under its flat rate and deductions. The net deposit is $2,396.08, 77.9% of gross; over the year that is $62,298 from $80,000, an effective rate of 22.1% 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 26 were identical, and the year's actual tax, $8,770, differs from the $8,770 withheld by $0, which becomes a refund 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.

Nearby salaries: what $60,000 to $115,000 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 every two weeks paycheck at 6 salaries from $60,000 to $115,000, single, standard W-4, no deductions. The effective rate climbs from 19.2% to 25.8% 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 $13,469 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.

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 $80,000 in Colorado, paid every two weeks, a single filer is withheld $337.31 per paycheck; married filing jointly (one income) $201.54, because the joint table doubles the standard deduction to $32,200 and widens every bracket; head of household $244.15, 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 $80,000 is $8,770 single and $5,240 married filing jointly on one income, a difference of $3,530 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 $2,422 a year on the single table. FICA is identical in every row, since it has no status.

The whole year on $80,000: withholding, tax due, and the settlement

26 paychecks of $3,076.92 withhold $8,770 of federal income tax over 2026. The tax actually due on the return, with the $16,100 standard deduction and no credits, is $8,770, so the year ends with a refund of about $0 — the gap between the withholding tables' approximation and the exact computation. The marginal rate on the last dollar is 22%; the effective rate on all taxes together is 22.1%. Social Security applies to every paycheck of the year, because $80,000 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 $2,812 for the year, 3.5% 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 $80,000 with these settings the year withholds $8,770 against $8,770 due, so the settlement is a refund 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 ($7,893 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 22%, 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 — $184.62 per paycheck on $80,000, well under the $24,500 annual limit — reduces federal and state taxable wages but not FICA wages, so it costs $135.88 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 $98.92. 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.

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 $84.62 per paycheck — the $2,200 credit spread over 26 paychecks — taking the net to $2,480.70. Checking box 2(c) for a second job raises it by $184.50, 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 $80,000 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.

$80,000 in Colorado against nine other states

Federal tax and FICA are the same everywhere; the state line is what moves. On $80,000 paid every two weeks, the nine states with no wage tax leave $2,504.22 per paycheck; California leaves $2,381.34, $122.88 less, or $3,195 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.

A raise on $80,000: 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 $80,000 in Colorado adds $92.31 of gross to a every two weeks paycheck and $60.89 of net, 66.0% 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.

Common mistakes

Trusting a calculator that does not state its tax year. Comparing net pay without entering deductions. The gap is the deductions. Taking a disagreement between two calculators as noise. For federal and FICA, one of them is wrong.

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.