Form W-4 Explained, Step by Step (2026)

Step 1: name, address, filing status

Step 1(c) picks one of three boxes — single or married filing separately, married filing jointly (or qualifying surviving spouse), head of household — and that choice selects the withholding table. It is the only line most people need to fill in; steps 2 to 4 are for situations the table cannot see. The married table has brackets twice as wide as the single one, so on $60,000 biweekly, single withholds $193.08 and married jointly withholds $109.23 per paycheck. Picking «married» when you will file jointly on one income is correct; picking it with two incomes and skipping step 2 is the most common cause of an April bill. Head of household — unmarried, paying more than half the cost of a home for a qualifying person — has its own table between the two.

Step 2: multiple jobs or a working spouse

Withholding assumes each paycheck is the household's only income, so a second job or a spouse's job is under-withheld unless step 2 says so. Three options: (a) the IRS online estimator, which produces a step 4(c) amount; (b) the multiple-jobs worksheet on page 3, which produces an amount for the higher-paying job's step 4(c); (c) the checkbox, on both W-4s, which switches each job to a table with half-width brackets. The box is exact when the two incomes are similar and rough when they are not. On two $60,000 salaries, without the box each is withheld $109.23 per paycheck and the household ends the year $4,360 short; with it, $193.08 each and the year balances. The dual income calculator runs any pair.

Step 3: dependents and credits

Step 3 is an annual amount, not a count: $2,200 per qualifying child under 17 and $500 per other dependent, plus any other credit you want reflected in withholding (education, foreign tax). The amount is subtracted from the year's tentative withholding in equal per-paycheck slices — $84.62 per biweekly paycheck for one child — and it applies only if income is under the credit's phase-out ($400,000 joint, $200,000 otherwise). One child on step 3 and head of household on step 1 lifts a $60,000 biweekly paycheck from $1,938.07 to $2,063.92. With two jobs, claim the children on one W-4 only; claiming them on both doubles the credit in withholding and produces a bill.

Step 4: other income, deductions, extra withholding

4(a) adds annual income with no withholding — interest, dividends, a side business, retirement distributions — so that the paycheck covers its tax; entering $10,000 of other income withholds an extra $46.15 per biweekly paycheck at the 12% bracket. 4(b) subtracts deductions you will take beyond the standard deduction (itemised deductions above $16,100 single or $32,200 joint; the deductions worksheet on page 3 computes the excess), reducing withholding. 4(c) adds a flat amount per paycheck, the simplest lever: $50 on line 4(c) takes a $60,000 paycheck from $1,938.07 to $1,888.07 and adds $1,300 to the year's withholding, which is how the multiple-jobs worksheet and the IRS estimator deliver their result.

Exempt, and the pre-2020 form

Writing «Exempt» in the space below 4(c) stops federal income tax withholding for the year, lawfully only if you had no tax liability last year and expect none this year; it expires on February 15 of the following year. FICA is unaffected. A W-4 from 2019 or earlier still on file is valid, and the employer computes withholding by the older allowance method, each allowance worth $4,300 of annual wage reduction. Employers cannot require a new form, but any change — a new job, a change in status — requires the current one, and the exempt guide covers the conditions.

When to file a new W-4

A new job, a marriage or divorce, a child, a spouse starting or stopping work, a second job, a large refund or bill last April, or a change in other income. The W-4 fixer above takes your salary, state, status, dependents and other income, computes the year's tax and withholding, and returns the exact step 3, 4(a), 4(b) and 4(c) values that close the gap — either to zero for the largest paycheck, or to a small refund if you prefer a margin. Give the form to your employer, not the IRS; it takes effect from the next payroll run or the one after.

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.

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.

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: $45,000 in California, paid twice a month

Take $45,000 a year in California, paid twice a month (24 paychecks), single, standard W-4, no pre-tax deductions. The gross per paycheck is $1,875.00. Federal income tax withholding, from the 2026 Publication 15-T percentage method, takes $134.17. Social Security takes 6.2% of gross, $116.25, and Medicare 1.45%, $27.19. California withholds $32.61 under its brackets and deductions. The net deposit is $1,564.78, 83.5% of gross; over the year that is $37,555 from $45,000, an effective rate of 16.5% 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 24 were identical, and the year's actual tax, $3,220, differs from the $3,220 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 $25,000 to $80,000 leave in California

A raise or a job offer is rarely at the round number on this page, so here is the ladder around it: the same twice a month paycheck at 6 salaries from $25,000 to $80,000, single, standard W-4, no deductions. The effective rate climbs from 11.7% to 22.6% 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 California takes a raise of roughly $12,921 in gross at this level, because the new dollars are taxed at the marginal rate rather than the average. The state column grows faster than the salary, since California's brackets rise with income; 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 $45,000 in California, paid twice a month, a single filer is withheld $134.17 per paycheck; married filing jointly (one income) $53.33, because the joint table doubles the standard deduction to $32,200 and widens every bracket; head of household $89.50, with its $24,150 deduction and its own brackets. Married filing separately uses the single table. California's own deductions and brackets follow the state’s own joint schedule, 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 $45,000 is $3,220 single and $1,280 married filing jointly on one income, a difference of $1,940 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.

The whole year on $45,000: withholding, tax due, and the settlement

24 paychecks of $1,875.00 withhold $3,220 of federal income tax over 2026. The tax actually due on the return, with the $16,100 standard deduction and no credits, is $3,220, 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 12%; the effective rate on all taxes together is 16.5%. Social Security applies to every paycheck of the year, because $45,000 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. California takes $783 for the year, 1.7% 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 $45,000 with these settings the year withholds $3,220 against $3,220 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 ($2,898 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 — $112.50 per paycheck on $45,000, well under the $24,500 annual limit — reduces federal and state taxable wages but not FICA wages, so it costs $94.50 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 $114.52. 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 $91.67 per paycheck — the $2,200 credit spread over 24 paychecks — taking the net to $1,656.45. Checking box 2(c) for a second job raises it by $94.37, 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 $45,000 in California; 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.

$45,000 in California against nine other states

Federal tax and FICA are the same everywhere; the state line is what moves. On $45,000 paid twice a month, the nine states with no wage tax leave $1,597.39 per paycheck; California leaves $1,564.78, $32.61 less, or $783 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.

Common mistakes

Married on step 1, two incomes, no step 2. The classic April bill. Children on both spouses' W-4s. Once. Step 3 as a headcount. It is dollars: $2,200 per child.

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.