As a first step to reflect the tax law changes, the IRS released new withholding tables
in January. These tables were designed to produce the correct amount of tax withholding — avoiding under- and over-withholding of tax — for those with simple tax situations. This means that people with simple situations might not need to make any changes. Simple situations include singles and married couples with only one job, who have no dependents, and who have not claimed itemized deductions, adjustments to income or tax credits.