In short
The 2026 W-4 has five steps: filing status, the multiple-jobs adjustment, dependent credits ($2,200 per child), other income and deductions, and your signature. Payroll annualizes your taxable wages, subtracts $12,900 (joint) or $8,600 (others) and runs the result through the Publication 15-T tables, so a single earner on $3,500 biweekly with $200 of 401(k) has $386 withheld per check. Two-earner couples should check the Step 2(c) box on both forms or they can be under-withheld by thousands.
Form W-4 tells your employer how much federal income tax to take out of each paycheck. Get it right and your withholding lands within a few hundred dollars of your actual tax; get it wrong and you either lend the IRS money all year or face a bill in April. This guide explains each of the five steps on the 2026 form, shows exactly how payroll turns your entries into a per-paycheck amount using IRS Publication 15-T, and covers the two situations that cause most under-withholding: two-earner couples and side income.
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The five steps of the 2026 Form W-4
The form has not used “allowances” since 2020. Instead you give your employer dollar amounts, and only Steps 1 and 5 are compulsory.
Step 1: personal information and filing status
Name, address, Social Security number and one of three boxes: Single or married filing separately, Married filing jointly (or qualifying surviving spouse), or Head of household. The status chooses the withholding table, so a married person who checks “Single” is over-withheld.
Step 2: multiple jobs or spouse works
If you hold two jobs, or you are married filing jointly and your spouse also works, each employer otherwise assumes its paycheck is the household’s only income and gives you a full standard deduction and full lower brackets. Three fixes are offered: use the IRS online estimator, use the Multiple Jobs Worksheet on page 3, or check the box in Step 2(c). The checkbox is accurate when the two incomes are roughly similar; check it on both W-4s, not just one.
Step 3: claim dependents and other credits
Enter $2,200 for each qualifying child under 17 and $500 for each other dependent, then add any other credits you expect, such as education credits. The total is divided across your paychecks and subtracted from withholding. Only do this on one job’s W-4, usually the higher-paying one.
Step 4: other adjustments
- 4(a) Other income not from jobs (interest, dividends, a side business), so tax on it is withheld from wages instead of paid quarterly.
- 4(b) Deductions you expect to claim above the standard deduction. If you itemize $22,000 as a single filer, enter $22,000 − $16,100 = $5,900.
- 4(c) Extra withholding: a flat dollar amount added to every paycheck, the simplest fix for a second earner or side income.
Step 5: sign
Unsigned forms are invalid: the employer withholds as if you were single with nothing else entered.
How Publication 15-T turns the form into a dollar amount
Your employer does not look up your salary in a chart. Automated payroll uses the percentage method in Publication 15-T, Worksheet 1A, in five moves:
- Annualize wages. Taxable wages for the period (gross minus pre-tax 401(k), health premiums and similar) multiplied by the number of pay periods, plus Step 4(a), minus Step 4(b).
- Subtract the Step 1 adjustment: $12,900 for married filing jointly or $8,600 for everyone else. This stands in for the standard deduction. If the Step 2(c) box is checked the adjustment is zero and a different table is used.
- Apply the annual percentage table for your status to the adjusted wage.
- Divide by pay periods and subtract the Step 3 credits divided by pay periods (not below zero).
- Add Step 4(c).
| Single: adjusted wage over | Married joint: adjusted wage over | Rate on the excess |
|---|---|---|
| $7,500 | $19,300 | 10% |
| $19,900 | $44,100 | 12% |
| $57,900 | $120,100 | 22% |
| $113,200 | $230,700 | 24% |
| $209,275 | $422,850 | 32% |
| $263,725 | $531,750 | 35% |
| $648,100 | $788,000 | 37% |
Each row also carries a fixed “tentative amount” for the tax on the rows below it, for example $5,800 at the single 22% line. With one job and no other income the result matches your real tax almost exactly.
Worked example: single, $3,500 every two weeks, $200 of 401(k)
- Taxable wages per period: $3,500 − $200 = $3,300. Annualized: $3,300 × 26 = $85,800.
- Less the single adjustment of $8,600: adjusted annual wage $77,200.
- Table row: over $57,900, tentative amount $5,800, 22% on the excess. ($77,200 − $57,900) × 22% = $4,246. Tentative tax = $5,800 + $4,246 = $10,046.
- Per paycheck: $10,046 ÷ 26 = $386.38.
Check: actual 2026 tax on $85,800 of wages is $85,800 − $16,100 = $69,700 taxable; $1,240 + $4,560 + ($19,300 × 22% = $4,246) = $10,046. The withholding is exact. FICA (6.2% + 1.45%) and state tax come out on top.
Two-earner couples: why the Step 2 box matters
Take a married couple where each spouse earns $85,000. If both file a W-4 marked Married filing jointly with nothing in Step 2, each employer computes: $85,000 − $12,900 = $72,100 adjusted wage; row over $44,100, tentative $2,480 plus 12% of $28,000 = $5,840 each, or $224.62 per biweekly paycheck. Combined withholding: $11,680.
Their actual joint tax on $170,000 is $170,000 − $32,200 = $137,800 taxable: $2,480 + $9,120 + ($37,000 × 22% = $8,140) = $19,740. They are under-withheld by $8,060 and will owe it in April, possibly with an underpayment penalty.
With the Step 2(c) box checked on both forms, the adjustment drops to zero and the checkbox table applies, which uses half-width brackets. Each employer computes: $85,000 adjusted wage; row over $66,500, tentative $5,800 plus 22% of $18,500 = $9,870 each, $379.62 per paycheck. Combined: $19,740, exactly right. The checkbox is exact only when the incomes are similar; if one spouse earns far more, use the worksheet or a Step 4(c) amount on the higher job.
Side income and other adjustments
If the single filer in the example above also earns $10,000 from freelancing, entering $10,000 in Step 4(a) raises the annualized wage to $95,000 and the tentative tax by $2,200 (the extra $10,000 at 22%), adding $84.62 to each biweekly paycheck. That covers the income tax but not self-employment tax, which is 15.3% on 92.35% of net profit; for that you either add a further amount in 4(c) or make quarterly payments through the quarterly estimated tax calculator. Estimated payments are due 15 April, 15 June, 15 September and 15 January if you expect to owe $1,000 or more after withholding.
Step 3 credits work in the opposite direction. The two-earner couple above with two children enters $4,400 on one W-4, and that job’s withholding falls by $4,400 ÷ 26 = $169.23 per paycheck, from $379.62 to $210.38.
Common mistakes
- Both spouses skipping Step 2. The single biggest cause of April tax bills: each employer gives you the full joint deduction and brackets, as the $8,060 shortfall above shows.
- Checking the Step 2 box on only one job. The checkbox table assumes the other job is doing the same; one box alone under-corrects.
- Claiming Step 3 credits on both jobs. The credit is then subtracted twice.
- Entering total itemized deductions in 4(b). Only the amount above the standard deduction goes there.
- Expecting the W-4 to cover self-employment tax. Step 4(a) handles income tax only.
- Never updating it. Marriage, a second job or a child all change the answer. Aim for at least 90% of this year’s tax, or 100% of last year’s, withheld or paid in; check mid-year with the paycheck calculator.
Frequently asked questions
How do I fill out a W-4 if I am single with one job?
Complete Step 1 (check Single) and Step 5 (sign). Add Step 3 only if you have dependents. The standard tables then withhold within a few dollars of your actual tax.
Should both spouses check the Step 2(c) box?
Yes, if both work and the incomes are similar. Each employer then uses the checkbox table with no $12,900 adjustment. If only one checks it, the household is still under-withheld.
What is the $12,900 or $8,600 deducted in Publication 15-T?
The Step 1 adjustment that stands in for the standard deduction when the Step 2 box is not checked: $12,900 for married filing jointly, $8,600 for everyone else. With the box checked it is zero.
Can I still claim 0 or 1 allowances?
No. Allowances were removed in 2020. Leaving Steps 2 to 4 blank is the equivalent of the old “0”; the old “1” roughly equals adding $4,300 in Step 4(b).
How do I get more money in each paycheck?
Claim every eligible dependent in Step 3, enter deductions above the standard amount in Step 4(b) and leave 4(c) at zero. Do not understate income; a balance over $1,000 at filing can carry a penalty.
Sources
- IRS Publication 15-T (2026) — Federal Income Tax Withholding Methods, Worksheet 1A — percentage method tables, Step 1 adjustments and the Step 2 checkbox schedule, checked 28 October 2026.
- IRS — Tax year 2026 inflation adjustments (IR-2025-103); Rev. Proc. 2025-32 — 2026 brackets and standard deduction used to verify the examples, checked 8 October 2026.
- Rev. Proc. 2025-32; IRC §24 — $2,200 child tax credit and $500 other-dependent credit for Step 3, checked 8 October 2026.
- IRS Publication 505; Form 1040-ES — estimated tax safe harbors and 2026 due dates, checked 8 October 2026.