W-4, Employee Withholding Allowance Certificate
Federal W-4 Form
State W-4 Form
Electronic W-4 Instructions
IRS and the Iowa Department of Revenue require all new employees to fill out a Form W-4, Employee Withholding Allowance Certificate. Form W-4 is used to determine how much income tax to withhold from employee wages. If an employee does not provide a W-4, the regulations instruct the employer to withhold taxes as if he or she is single, with no withholding allowances.
Income Tax is a pay-as-you-go tax. You must pay the tax as you earn or receive income during the year. The W-4 Form remains in effect until the employee completes and submits a new one. Employees should check their withholding during the year if the tax laws change or if there are changes in their financial or personal situation.