A number of law changes go into effect in 2013 that will result in employees seeing smaller paychecks, including the expiration of the payroll tax cut, the increase in the Social Security taxable wage base, and the new 0.9% Medicare tax imposed on high wage earners. This article explains the changes and provides illustrations to show their effect on workers' paychecks.

WASHINGTON — Following the January tax law changes made by Congress under the American Taxpayer Relief Act (ATRA), the Internal Revenue Service announced today it plans to open the 2013 filing season and begin processing individual income tax returns on Jan. 30.