How many days does an employer have to implement a revised W-4?

Employers are required to implement a revised Form W-4, which is the Employee's Withholding Certificate, within 30 days of receiving the completed form from an employee. This timeframe ensures that the changes in an employee's withholding allowances are processed timely, which can impact the amount of federal income tax withheld from their wages.

The 30-day requirement is aligned with IRS regulations meant to keep withholding accurate and up-to-date, reflecting an employee's current tax situation. An employer's timely implementation of the revised W-4 helps to ensure compliance with tax laws and minimizes the risk of under-withholding or over-withholding that could affect employees' tax returns. This practice supports both the employer's and employee's responsibilities regarding federal tax compliance.