IRS Form W-4 — the Employee's Withholding Certificate that determines how much federal income tax to withhold from each paycheck.
Form W-4 (Employee's Withholding Certificate) is the IRS form each US employee completes when starting a new job — and any time their tax situation changes — to tell the employer how much federal income tax to withhold. The form was substantially redesigned in 2020 to remove allowances and instead use clearer dollar-amount inputs based on filing status, multiple jobs, dependents, and additional withholding requests.
Employers use the W-4 plus the IRS Publication 15-T tables (or the percentage method) to calculate federal income tax withholding each pay period. The W-4 is not filed with the IRS — it stays in the employee's personnel file. Employees should review and update their W-4 annually or after major life events (marriage, divorce, new dependent, second job, large changes in deductions).
A new W-4 must be on file before any pay is processed; absent a W-4, the employer must withhold as if the employee were a single filer with no other adjustments. Many states have their own state-tax equivalent (CA DE-4, NY IT-2104, etc.) that should be collected alongside the federal W-4. Modern HRIS platforms collect W-4s electronically as part of the onboarding flow.
Our onboarding flow has every new hire fill out a digital W-4 and any state-tax form before their first day.
Peoplifi unifies HR, payroll, time tracking, and performance into one modern platform — so concepts like W-4 stay handled, not stuck in spreadsheets.
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