IRS Form W-4, Employee's Withholding Allowance Certificate, also known as the IRS Employee Withholding form, is a document completed by employees to let the employer know how much money to withhold from their paychecks for federal taxes. The Internal Revenue Service (IRS) recommends submitting a new IRS W-4 Form each year and whenever your financial or personal situation undergoes changes.
The form is released by the IRS annually with the 2019 version used for the 2018 tax return. All previous editions are rendered obsolete with the appearance of the new version. A fillable W-4 Form is available for download below.
W-4 Form due date depends on the payroll period. Employers must implement a new form by the start of the first payroll period. For example, if you give your employer an employee's withholding allowance certificate form on August 10 and you are paid on the 15th and the 30th of each month, the employer has to implement the form no later than the September 15 payroll. It can be done earlier, but no law requires it.
There is no time limit for the form, it remains in effect until the employee decides to change it. It must be kept in the employee's payroll folder as verification of the amount of the federal income tax withheld.