A W-4 (Employee's Withholding Certificate) is the form you give your employer to tell them how much federal income tax to withhold from each paycheck. It does not go to the IRS — your employer uses it to calculate withholding, which is submitted to the IRS on your behalf. The current W-4 design (redesigned in 2020) uses a 5-step form without the old "allowances" system. You must complete a new W-4 when you start a job; you can update it anytime.

Who needs to complete Steps 2, 3, and 4 of the W-4?

Most single-job workers with straightforward situations only need to fill out Steps 1 (personal info) and 5 (signature). Step 2 (required if you have multiple jobs or a working spouse), Step 3 (optional if you have qualifying dependents for the child tax credit), and Step 4 (optional for other income, deductions, or extra withholding) are only needed in specific situations. Leaving Steps 2–4 blank does not cause an error — it means your employer uses the standard withholding rate for single filers.

What happens if I withhold too little or too much?

Too little: you owe taxes at filing time plus potentially an underpayment penalty (if you owe $1,000+ and paid less than 90% of this year's tax or 100% of last year's tax). Too much: you get a refund — but you have given the IRS an interest-free loan for up to 15 months. A large refund is not free money; it is your own money you could have had in your paycheck. Goal: withhold as close to your actual tax liability as possible, so you neither owe nor receive a large refund.

When should I update my W-4?

Update your W-4 when: you get married or divorced, you have a child (qualifies for child tax credit), your spouse starts or stops working, you take a significant second job, you have major investment income (not covered by withholding), or you receive a significant raise that moves you to a higher bracket. After any major life event, use the IRS Withholding Estimator (irs.gov/W4app) or our W-4 Calculator to check whether your current withholding is accurate for the full year.

What should I put on my W-4 to withhold the most taxes?

To maximise withholding (get a larger refund): on Step 4(c), enter an additional dollar amount per paycheck to withhold beyond the standard calculation. You can specify any amount. Alternatively, write "Single" in Step 1 even if married — single withholding rates are higher than married. To minimise withholding (maximise take-home pay): complete Step 3 to claim the Child Tax Credit and Step 4(b) to claim expected deductions above the standard deduction. Our W-4 Calculator can calculate the exact additional withholding or deduction amount for your situation.

How to Fill Out a W-4 in 2026: Step-by-Step for Every Situation

The 2020+ W-4 uses a five-step form without withholding allowances. Step 1 is basic info; Step 2 handles multiple jobs; Step 3 claims dependents; Step 4 adds other income or deductions; Step 5 is your signature. Most single-job workers only need to complete Steps 1 and 5.

To fill out a W-4, complete Step 1 (personal information and filing status) and Step 5 (signature) — all other steps are optional and only required in specific situations. If you have one job, are single, and have no dependents, you can leave Steps 2–4 blank and your withholding will default to the correct single-filer rate. The most common mistakes are skipping Step 2 when a spouse also works (leading to underwithholding and a tax bill in April) or failing to claim dependents in Step 3 (leaving money with the IRS instead of in your paycheck).

The W-4's five steps explained

W-4 Form 2020+ — Five Steps Explained

Step 1

Personal Information

Required

Name, address, SSN, filing status (Single / Married Filing Jointly / Head of Household)

Step 2

Multiple Jobs or Spouse Works

Optional

Complete ONLY if you have 2+ jobs simultaneously or are MFJ and spouse also works. Use IRS estimator for accuracy.

Step 3

Claim Dependents

Optional

If total income ≤$200k (single) or ≤$400k (MFJ): $2,000 per qualifying child under 17; $500 per other dependent.

Step 4

Other Adjustments

Optional

4(a): Other income not from jobs (dividends, retirement). 4(b): Deductions above standard. 4(c): Extra withholding per paycheck.

Step 5

Signature

Required

Sign and date. Unsigned W-4s are invalid and employer must withhold at Single, No Adjustments rate.

Most single-job workers only need to complete Steps 1 and 5

Step-by-step instructions for common filing situations

Situation 1: Single, one job, no dependents

This is the simplest case:

Step 1: Enter your name, address, SSN, and check "Single or Married filing separately."
Steps 2–4: Leave blank.
Step 5: Sign and date.

Your employer will withhold at the standard single rate. You will likely receive a small refund or owe a small amount at filing, depending on deductions.

Situation 2: Married filing jointly, both spouses work

This is where most underwithholding happens. When two people each complete a W-4 at their individual jobs using "Married Filing Jointly" with no Step 2 adjustment, each employer withholds as if that is the household's only income — but the combined income pushes you into a higher tax bracket. Result: a tax bill in April.

To fix this, use one of three options in Step 2:

2a (most accurate): IRS Tax Withholding Estimator at irs.gov/W4App. Spouses fill out W-4s simultaneously. Takes 10–15 minutes but gives the best accuracy.
2b (accurate): Multiple Jobs Worksheet on the W-4 instructions. Work through the table together and enter the extra withholding amount in Step 4(c).
2c (simple): Check the box in Step 2(c). This tells both employers to withhold at a higher rate. Works best when both spouses earn similar amounts.

Situation 3: Head of household with dependents

Step 1: Check "Head of household" filing status.
Step 3: Enter the total child/dependent credit amounts. For each child under 17: multiply by $2,000. For each other qualifying dependent: multiply by $500. Enter the total on line 3.
Steps 2 and 4: Only if you have multiple jobs.
Step 5: Sign and date.

Claiming dependents in Step 3 reduces the tax withheld from each paycheck — you get larger paychecks now rather than a large refund later. This is mathematically correct: a refund is an interest-free loan to the government.

Situation 4: Self-employed income or freelance work alongside your job

If you earn significant income not subject to withholding (1099 income, dividends, rental income, side business), you have two options:

Step 4(a): Enter the estimated annual amount of non-job income. Your employer will increase withholding to cover it.
Alternatively, make quarterly estimated tax payments directly to the IRS (Form 1040-ES) — often cleaner if self-employment income is large or variable.

When to submit a new W-4

Life event	Why it matters	Action
Got married	Filing status changes; spouse's income affects bracket	New W-4 + use IRS estimator for both
Had a child	New $2,000 child tax credit per qualifying child	Update Step 3 to reduce withholding
Divorced or separated	Filing status changes from MFJ to Single or HoH	New W-4 immediately
Started second job	Combined income triggers higher bracket	Complete Step 2 on both W-4s
Bought a home	Mortgage interest may push you to itemize deductions	Use Step 4(b) if itemised deductions exceed standard
Owed taxes last April	Withholding was insufficient	New W-4 + add extra withholding in Step 4(c)
Large refund last year	Overwithholding — lost time value of money	Reduce withholding by adjusting Step 3 or removing Step 4(c) extras

How to adjust withholding without a new job

You can submit a new W-4 to your employer at any time during the year — you do not have to wait for a new job or a life event. Your employer must implement the new withholding within 30 days of receiving the form.

If you expect to owe taxes at year-end and want to catch up without changing your W-4, you can make a direct estimated tax payment to the IRS using EFTPS.gov or by mailing Form 1040-ES.

Step 4(c): Requesting extra withholding

Step 4(c) lets you request a specific additional dollar amount withheld from each paycheck — on top of normal withholding. This is useful when:

You owed taxes last year and want to prevent it this year
You have significant non-W2 income but prefer not to make quarterly payments
You want to use overwithholding as a forced savings mechanism (not financially optimal, but a behaviour some people prefer)

Example: if you owed $1,200 last year and have 24 remaining pay periods, enter $50 in Step 4(c) to withhold $50 extra per paycheck for the rest of the year.

Key takeaways

Most single workers with one job only need to complete Steps 1 and 5 — everything else is optional.
Married couples where both spouses work must complete Step 2 or face a tax bill in April — underwithholding is the most common W-4 mistake.
Claim dependents in Step 3 to increase your take-home pay throughout the year instead of getting a large refund.
Submit a new W-4 within 30 days of any major life change: marriage, divorce, new child, second job, or home purchase.
Use Step 4(c) to request extra withholding if you owed taxes last year or have significant non-W2 income.

Frequently asked questions

How do I fill out a W-4 if I am single with one job?

Enter your name, address, and SSN in Step 1. Check "Single or Married filing separately." Leave Steps 2–4 blank. Sign in Step 5. Your withholding will default to the standard single-filer rate — no further action needed unless your situation changes.

What happens if I do not fill out a W-4?

If you do not submit a W-4 or submit one without a signature, your employer must withhold at the default rate: Single, No Adjustments. This often results in overwithholding for married employees or those with dependents. Submit a W-4 to get accurate withholding.

Should I claim 0 or 1 allowances on my W-4?

The 2020 redesigned W-4 no longer uses the allowances system (0, 1, 2). If you have a pre-2020 W-4 on file, it remains valid but the new form is more accurate. Submit an updated W-4 using the new format for correct withholding.

How do I change my W-4 withholding?

Submit a new W-4 to your HR or payroll department. You can do this at any time during the year. Changes take effect within the next 1–2 pay periods (your employer has 30 days to implement the change). There is no limit on how often you can update your W-4.

What should married couples put on their W-4?

Both spouses should check "Married Filing Jointly" in Step 1. On at least one spouse's W-4, complete Step 2 using the IRS Tax Withholding Estimator (most accurate), the Multiple Jobs Worksheet, or by checking Step 2(c) (simplest, works best when incomes are similar). Skipping Step 2 on both forms almost always results in underwithholding.