Even if you’re usingpayroll software that automatically updates for payroll tax changes, Circular E — The IRS Employer Tax Guide — is a handy resource to have on your desk.

Offering more than just payroll withholding tables, Circular E can settle many of your payroll-related questions, such as definitions of employees, when certain payroll taxes are due and what are the lookback periods for employers.

The latest version of the IRS2011 Circular Eprovides insight into recent federal tax law changes including the 2% Social Security payroll tax cut, as well as important government contact numbers.