Guides · W-4 form

US Form W-4 explained

The W-4 is the form you give your employer to set how much federal income tax is withheld from each paycheck. The current version (post-2020 redesign) dropped the "allowances" model and replaced it with a simpler stepped structure. Every line has a purpose; some apply to you and some do not. Here is every step, every line.

Why the W-4 matters

Your employer withholds federal income tax from each paycheck based on the W-4 you have on file. Too little withheld and you owe at year-end (plus possible underpayment penalty). Too much and you get a refund — interest-free, after the year closes.

The W-4 is the only lever you control over withholding mid-year. Updating it once, in January or after a life change, is the difference between a clean year-end and an unwelcome surprise.

Before 2020 — the allowances version

Pre-2020 W-4s asked you to claim allowances. Each allowance was a personal exemption (you, your spouse, dependents) plus deductions. The total allowances × $4,200 (the 2019 personal exemption) was subtracted from gross income before the employer applied the withholding tables.

That worked most of the time but had well-known failure modes: married couples who both worked and didn't adjust for each other's income; people who claimed more allowances than they had; people who didn't update the W-4 after a raise.

After 2020 — the stepped version

The 2020 redesign removed allowances entirely. The new W-4 is five steps:

  1. Personal info (name, SSN, filing status).
  2. Multiple jobs or spouse works (checkbox or worksheet).
  3. Claim dependents (multiplied by $2,000/dependent credit).
  4. Other adjustments (income, deductions, extra withholding).
  5. Sign.

The employer feeds Step 1 + Step 3 into the IRS Publication 15-T withholding tables. Step 2 adjusts for multiple jobs. Step 4 lets you fine-tune for non-standard situations.

Step 1: Personal info

Name, address, SSN, and filing status. Three filing-status options on the W-4 itself:

  • Single or married filing separately — for people who are not married or who are married but file separately.
  • Married filing jointly or qualifying widow(er) — for married couples who file jointly, or surviving spouses for up to two years after the death of a spouse.
  • Head of household — for unmarried people who pay more than half the cost of keeping up a home for a qualifying person.

The withholding tables treat the three statuses differently. If you select "married filing jointly" but actually file as single, withholding will be too low — you will owe at year-end.

Step 2: Multiple jobs or spouse works

If you have only one job and no working spouse, leave Step 2 blank and your employer withholds the standard amount for your filing status.

If you have multiple jobs, or your spouse works, check the box. The IRS's Tax Withholding Estimator or the multiple-jobs worksheet will produce an extra amount to add to withholding at one job (typically the highest-paying one).

Why this matters: each employer treats its own paycheck as if it were your only income. Two $50,000 jobs each withhold as if you earn $50,000. Together they under-withhold for a $100,000 combined income that crosses into the 22% bracket.

The 2020 redesign stopped using "Married" status alone to flag dual-income households. The Step 2 checkbox is the replacement.

Step 3: Claim dependents

Multiply the number of qualifying children under 17 by $2,000. Multiply other dependents by $500. Total these. Enter on Step 3.

The $2,000-per-child is the Child Tax Credit. It phases out above $400,000 for married filing jointly ($200,000 for all other statuses), but for most employees the full credit is applied.

Note: the W-4 doesn't actually claim the credit — it tells the employer to withhold less, which has the effect of spreading the credit across the year. The actual credit is claimed on Form 1040.

Step 4: Other adjustments (optional)

Step 4 is where you fine-tune. Five optional sub-lines:

  • 4(a) Other income (not from jobs) — interest, dividends, retirement income. Adding this on the W-4 makes the employer withhold more, so the year-end reconciliation doesn't produce a balance due.
  • 4(b) Deductions — itemized deductions or extra standard deduction. Setting this reduces withholding.
  • 4(c) Extra withholding — flat dollar amount per pay period to withhold in addition to the standard tables. Used by people who consistently owe at year-end.

Most employees leave Step 4 blank. It is for specific situations:

  • Significant investment income → fill in 4(a).
  • Itemizing on Schedule A → fill in 4(b) to reduce withholding.
  • Two-job couples where Step 2 worksheet gave a number → fill in 4(c).

Step 5: Sign here

Sign and date. The IRS requires the signature under penalty of perjury. The form is valid indefinitely — until your circumstances change.

Common scenarios worked through

Single, one job, no dependents, no other income

Step 1: single. Step 2: blank. Step 3: blank. Step 4: blank. Step 5: sign. Your employer withholds using the standard single-job tables. Done.

Married, both work, two kids

Step 1: married filing jointly. Step 2: checkbox (or worksheet result). Step 3: 2 × $2,000 = $4,000. Step 4: blank if both jobs use the standard tables. Step 5: sign. Withholding at the higher-earning job includes the $4,000 dependent credit; withholding at the second job should add the Step 2 worksheet result.

Single, side gig as 1099 contractor

Step 1: single. Step 2: checkbox (the W-2 + 1099 counts as multiple jobs). Step 4(a): enter the 1099 expected net earnings. The employer will withhold more on each W-2 paycheck to cover the additional tax on the 1099 income. Step 5: sign. Alternatively, skip the W-2 adjustment and pay quarterly estimated tax via Form 1040-ES.

Two-earner couple with one high earner and one part-time

Step 1: married filing jointly. Step 2: checkbox on the high-earner's W-4; leave blank on the part-timer's. Step 3: blank if no qualifying children. Step 5: sign. The high-earner's employer adjusts withholding to account for both incomes.

When to update

The IRS encourages employees to re-do the W-4 each year. The most common triggers:

  • January — annual reset.
  • Raise or promotion.
  • Spouse starts or stops working.
  • New job.
  • Marriage, divorce, new dependent.
  • Major change in deductions (itemizing for the first time, large HSA contribution).
  • Year-end refund or balance due surprises.

Use the IRS Tax Withholding Estimator — a free interactive tool that produces a personalized W-4. Submit the result to your employer; the new withholding applies to the next pay period.