Under pre-Act law, taxpayers determined their taxable income by subtracting from their adjusted gross income any personal exemption deductions. Personal exemptions generally were allowed for the taxpayer, the taxpayer’s spouse, and any dependents. The amount deductible for each personal exemption was scheduled to be $4,150 for 2018, subject to a phaseout for higher earners.

New law. For tax years beginning after Dec. 31, 2017 and before Jan. 1, 2026, the deduction for personal exemptions is effectively suspended by reducing the exemption amount to zero.