What form determines the amount of income tax withheld from a payroll check?

The W-4 form is essential in determining the amount of income tax withheld from an employee's paycheck. When an employee starts a job, they fill out the W-4 to indicate their tax situation to their employer. This form includes information on filing status, number of allowances, and additional withholding amounts, which helps employers calculate the correct amount of federal income tax to withhold from each paycheck. This process ensures that employees have the appropriate amount withheld throughout the year based on their personal financial situation, potentially avoiding large tax bills at the end of the year.

The W-2 form, on the other hand, is provided by the employer at the end of the tax year and summarizes the employee's earnings and tax withholdings for that year, but does not determine how much is withheld from each paycheck. The 401K form relates to retirement savings contributions and does not have any direct connection to income tax withholding. The W-9 form is used to request the Taxpayer Identification Number and certification for various types of payments, primarily for independent contractors, and again does not influence the income tax withheld from payroll checks.