Definition
The W-4, formally titled 'Employee's Withholding Certificate,' is the IRS form you give to your employer to tell them how much federal income tax to withhold from your paycheck. Employers are legally required to withhold based on the most recent W-4 you've submitted.
The current W-4 design — overhauled in 2020 — has five steps. Step 1 collects your name and filing status. Step 2 handles multiple-job situations. Step 3 lets you claim dependent tax credits. Step 4 covers other income, deductions, and extra withholding. Step 5 is your signature. Most single-job employees only need to complete Steps 1 and 5; the rest are optional adjustments.
You can submit a new W-4 to your employer at any time — there's no annual requirement and no limit on changes.
How this affects your W-4
The W-4 is the direct mechanism for adjusting your withholding. Every calculation this tool produces translates directly into W-4 line entries: your filing status in Step 1c, your dependent credits in Step 3, and any extra per-paycheck withholding in Step 4c.
Your employer must put a new W-4 into effect by the start of the first payroll period ending on or after the 30th day after you submit it, and many do it sooner.
See how w-4 form affects your withholding
Use the free W-4 calculator to calculate your exact withholding with your specific situation.
Open the W-4 Calculator →Read the guide
How to Fill Out a W-4 Form in 2026: Complete Step-by-Step Guide
Complete walkthrough of all five W-4 steps for 2026 — from filing status to extra withholding, the new OBBBA deductions, common mistakes and when to update.
How to Fill Out a W-4 for a New Job (2026 Step-by-Step)
Starting a new job and staring at a blank W-4? This guide walks you through all 5 steps — including what to do if you have a second job or your spouse works.
Related terms
Withholding
Taxes your employer takes out of each paycheck and sends to the IRS and your state before you receive your pay.
Filing Status
Your tax category based on marital and household situation — determines your tax brackets and standard deduction.
Step 4c — Extra Withholding
A line on the W-4 where you specify a flat dollar amount to withhold from every paycheck in addition to the calculated amount.