The IRS released the completely redesigned calendar year 2020 Form W-4 on December 4, 2019. The form was overhauled to comply with the 2017 federal tax reform law. Employers use Form W-4 to calculate each employee's income tax withholding. Beginning in 2020, an employee's income tax withholding is determined based on the employee's tax status and adjustments (allowances have been eliminated). The 2020 form also contains a new tax status: Head of Household.