Form W-4

What the form covers

The current design, introduced for 2020, removed withholding allowances. It has five steps:

• Step 1: name, address, Social Security number and filing status (single or married filing separately, married filing jointly, or head of household). Required.
• Step 2: multiple jobs or a spouse who works. Optional, but skipping it often leads to under-withholding for two-income households.
• Step 3: credits for dependents, reducing withholding.
• Step 4: other adjustments: other income, deductions beyond the standard deduction, and extra withholding per pay period.
• Step 5: signature and date. A W-4 without a signature is not valid.

The employer then enters payroll inputs into the system and uses the IRS withholding tables in Publication 15-T to calculate federal income tax. The W-4 does not affect Social Security or Medicare withholding, which are set by FICA rates.

Employer rules that trip people up

• No form returned. If a new employee does not submit a W-4, withhold as if they were single or married filing separately with no other entries.
• Invalid forms. If the form is altered or the employee indicates it is false, treat it as invalid, ask for a new one, and keep using the previous valid form (or the single default for a new hire).
• Timing of changes. When an employee hands in a new W-4, it must take effect no later than the start of the first payroll period ending on or after the 30th day after you receive it.
• Exempt status. Employees who claim exemption must give a new W-4 by February 15 each year to keep it. If they do not, withhold as single or married filing separately with no adjustments, or using their last valid non-exempt form.
• Lock-in letters. If the IRS sends a lock-in letter for an employee, withhold at the rate the IRS specifies and ignore any W-4 that would lower it.
• No tax advice. HR and payroll should not tell employees how to fill in the form. Point them to the IRS Tax Withholding Estimator instead.
• Older forms. Employees hired before 2020 do not have to submit a new design form unless they want to change withholding.

Where it sits in onboarding

The W-4 is part of standard new hire paperwork, usually completed alongside Form I-9, direct deposit and state forms in a digital onboarding flow before the first payroll run. Collecting it electronically is allowed if the system meets IRS requirements for electronic signatures and verification.

It also feeds state new hire reporting: the employee details on the W-4 are what most states require employers to report within about 20 days of hire.

State withholding forms

Most states with an income tax have their own withholding certificate, such as California's DE 4 or New York's IT-2104. Some states accept the federal W-4; many do not, especially since the 2020 redesign removed allowances. Remote employees complicate this: withholding usually follows the state where the work is performed, so a remote hire may need a different state form from your office staff. Rules vary by state.

Record-keeping

Keep each W-4 for at least four years after the tax becomes due or is paid, in line with the general IRS rule for employment tax records. Store it in the payroll or personnel file with restricted access, since it contains a Social Security number. Provide it to the IRS only if they request it.

Common mistakes

• Entering filing status wrong in the payroll system. Many withholding complaints trace back to a data entry error, not the form.
• Letting exempt claims roll over after February 15.
• Missing state forms for remote hires in other states.
• Collecting the W-4 on paper on day one, then keying it late so the first paycheck uses the wrong withholding. Accurate payroll deductions start with collecting forms during preboarding.