What changed on the 2020 W-4 form?

The 2020 W-4 eliminated withholding "allowances" entirely. Instead of claiming 0, 1, or 2 allowances, the new form uses dollar amounts for deductions, income, and extra withholding. Filing status is still Step 1, but Steps 2–4 directly affect the dollar amount withheld.

Do I need to fill out a new W-4?

If you were hired before 2020 and your situation hasn't changed, your old W-4 (with allowances) is still valid and your employer can continue using it. However, if you start a new job, change jobs, or have a major life change (marriage, new child, second job), you should complete the current W-4 to ensure accurate withholding.

What happens if I only fill out Steps 1 and 5?

If you only complete Steps 1 (personal info/filing status) and 5 (signature), your withholding is calculated as if you have one job, no other income, and take only the standard deduction. This is correct for many single-income households, but will likely under-withhold for people with multiple jobs or significant other income.

W-4 Withholding Guide (2026) — How to Fill Out Your W-4 Form

What is the W-4 and why does it matter?

The W-4 (Employee's Withholding Certificate) tells your employer how much federal income tax to withhold from each paycheck. The form you complete directly controls your paycheck — get it right and you get the right amount withheld. Get it wrong and you either owe money at tax time (under-withholding) or receive a large refund (over-withholding, meaning you gave the IRS an interest-free loan).

The W-4 only affects federal income tax withholding. It does not affect Social Security, Medicare, or state income tax withholding.

What changed in 2020?

The IRS completely redesigned the W-4 form in 2020, making the biggest change since 1987. The key change: withholding allowances are gone.

The old system used allowances — claiming more allowances meant less withholding. The new system uses actual dollar amounts, making the math transparent but less intuitive to many employees.

Old W-4 (pre-2020)	New W-4 (2020+)
Withholding allowances (0, 1, 2…)	Dollar-based adjustments
Personal exemptions (eliminated in 2018)	Child tax credit amounts
Single/Married checkbox	Single / MFJ / Head of household
Simple but opaque	More complex but transparent

If you filed a W-4 before 2020 and haven't changed jobs since, your employer can continue using the old form. But for any new job or life change, you'll complete the current version.

W-4 Step by step

Step 1 — Personal information and filing status (required)

Enter your name, address, Social Security number, and filing status. Choose from:

Single or Married filing separately — highest withholding per dollar
Married filing jointly or qualifying surviving spouse — lower withholding rate
Head of household — intermediate withholding; requires that you pay more than half the cost of keeping up a home for a qualifying person

Many single employees who also have a second job choose "Single" even if married, to avoid under-withholding. This is conservative but safe.

Step 2 — Multiple jobs or spouse works (optional but important)

This step is critical if you or your spouse have more than one job. Each employer withholds as if the wages they pay are your entire income. If you have two jobs, each applying a low rate, your combined income could push you into a higher bracket — resulting in under-withholding.

Three options to handle this:

Use the IRS online estimator (most accurate) — the IRS Withholding Estimator calculates exact amounts
Use the Multiple Jobs Worksheet (included with W-4 instructions) — table-based calculation
Check the box in Step 2(c) — simple checkbox that tells the employer to use the Married withholding rate tables for single filers; this works if both jobs pay similar amounts

Step 3 — Claim dependents (optional)

If your total income is $200,000 or less ($400,000 or less for MFJ), you can claim the Child Tax Credit here. Multiply qualifying children under 17 by $2,000, plus $500 per other qualifying dependent. This reduces your withholding by the full credit amount divided by your pay periods.

Example: 2 qualifying children = $4,000 credit. Annual withholding reduced by $4,000 = $153.85/biweekly period less withheld.

Step 4 — Other adjustments (optional)

Three sub-steps:

4(a) Other income — if you have significant non-wage income (freelance, investments, alimony), enter the annual amount here. This raises your withholding to cover that income.
4(b) Deductions — if you plan to itemize, enter the expected deductions above the standard deduction from the Deductions Worksheet. This lowers withholding.
4(c) Extra withholding — enter a flat dollar amount to add to each paycheck's withholding. Useful if you owe taxes annually and want to fix it without changing other steps.

Step 5 — Signature (required)

Sign and date. You're done.

Common W-4 mistakes and how to fix them

Two jobs, old W-4: If you used an old W-4 with allowances and added a second job, you're likely under-withheld. Complete a new W-4 using Step 2.
Got married but didn't update: Marriage can lower your withholding rate if both spouses work. Update Step 2 to account for combined income.
Had a child but didn't update: A new child may qualify for the Child Tax Credit — enter it in Step 3 to reduce withholding appropriately.
Large freelance income: Side income is not subject to employer withholding. Enter the annual amount in Step 4(a) or make quarterly estimated payments.

Should I claim "exempt" from withholding?

You can write "Exempt" on the W-4 only if you had no federal income tax liability last year AND expect none this year. This is rare — most employees with significant income do not qualify. If you mistakenly claim exempt, you could owe a large tax bill plus penalties.

How often should I update my W-4?

Update your W-4 whenever you have a major life or tax change:

New job or second job
Marriage or divorce
Birth or adoption of a child
Large change in itemized deductions
Significant investment income
After filing your taxes and finding you owed or got a large refund

Use the paycheck calculator to verify your withholding

After completing your W-4, use the calculators below to estimate whether your withholding looks right. Compare the calculator's output to your actual pay stub:

Last updated: January 2026 · Source: IRS Form W-4 (2026), IRS Publication 505