Updated Withholding Calculator, Form W-4 Released; Calculator Helps Taxpayers Review Withholding Following New Tax Law Posted on March 1, 2018March 1, 2018 by Kawa Ascenzi Corbishley & Carroccio Posted in IRS, Taxpayers, Tips The IRS urges taxpayers to use these tools to make sure they have the right amount of tax taken out of their paychecks. Source: Updated Withholding Calculator, Form W-4 Released; Calculator Helps Taxpayers Review Withholding Following New Tax Law | Internal Revenue Service