The Tax Cuts and Jobs Act passed in December 2017 made considerable changes to tax withholding. Personal and dependent exemptions are no more and the new law enhanced the pre-existing child tax credit.
The personal allowance worksheet reflects these effects, adjusting Lines B through H extensively. Line D on the 2017 form specifically references the number of dependents a person can claim on his or her tax return - which, as mentioned, tax reform eliminated. Line H on the 2017 form is an accumulation of lines A through G - which indicate dependents and the child tax credit. On the 2018 form, Line E outlines the child tax credit, which has updated requirements.
Take a closer look at the differences in the infographic below. The most important pieces have been outlined in green boxes.
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