26 USC 151 – Allowance of deductions for personal exemptions
(a) Allowance of deductions
In the case of an individual, the exemptions provided by this section shall be allowed as deductions in computing taxable income.
(b) Taxpayer and spouse
An exemption of the exemption amount for the taxpayer; and an additional exemption of the exemption amount for the spouse of the taxpayer if a joint return is not made by the taxpayer and his spouse, and if the spouse, for the calendar year in which the taxable year of the taxpayer begins, has no gross income and is not the dependent of another taxpayer.
(c) Additional exemption for dependents
An exemption of the exemption amount for each individual who is a dependent (as defined in section 152) of the taxpayer for the taxable year.
(d) Exemption amount
For purposes of this section—
(1) In general
Except as otherwise provided in this subsection, the term “exemption amount” means $2,000.
(2) Exemption amount disallowed in case of certain dependents
In the case of an individual with respect to whom a deduction under this section is allowable to another taxpayer for a taxable year beginning in the calendar year in which the individual’s taxable year begins, the exemption amount applicable to such individual for such individual’s taxable year shall be zero.
(3) Phaseout
(A) In general
In the case of any taxpayer whose adjusted gross income for the taxable year exceeds the applicable amount in effect under section 68(b), the exemption amount shall be reduced by the applicable percentage.
(B) Applicable percentage
For purposes of subparagraph (A), the term “applicable percentage” means 2 percentage points for each $2,500 (or fraction thereof) by which the taxpayer’s adjusted gross income for the taxable year exceeds the applicable amount in effect under section 68(b). In the case of a married individual filing a separate return, the preceding sentence shall be applied by substituting “$1,250” for “$2,500”. In no event shall the applicable percentage exceed 100 percent.
(C) Coordination with other provisions
The provisions of this paragraph shall not apply for purposes of determining whether a deduction under this section with respect to any individual is allowable to another taxpayer for any taxable year.
(4) Inflation adjustment
Except as provided in paragraph (5), in the case of any taxable year beginning in a calendar year after 1989, the dollar amount contained in paragraph (1) shall be increased by an amount equal to—
(A) such dollar amount, multiplied by
(B) the cost-of-living adjustment determined under section 1(f)(3) for the calendar year in which the taxable year begins, by substituting “calendar year 1988” for “calendar year 2016” in subparagraph (A)(ii) thereof.
(5) Special rules for taxable years 2018 through 2025
In the case of a taxable year beginning after December 31, 2017, and before January 1, 2026—
(A) Exemption amount
The term “exemption amount” means zero.
(B) References
For purposes of any other provision of this title, the reduction of the exemption amount to zero under subparagraph (A) shall not be taken into account in determining whether a deduction is allowed or allowable, or whether a taxpayer is entitled to a deduction, under this section.
(e) Identifying information required
No exemption shall be allowed under this section with respect to any individual unless the TIN of such individual is included on the return claiming the exemption.