W-4(redirected from W4)
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A form that employees fill out when starting a job in the United States. The form calculates the tax withholding from an employee's paychecks, depending on the number of persons in his/her household and the employee's expected filing status for that year. The W-4 form does not determine one's tax liability; one may receive a refund (or be required to pay extra) depending on his/her specific deductions, credits and income.