1. Short title This Act may be cited as the Child Tax Credit Extension Act . 2. Permanent increase and modification of child tax credit (a) Increase in credit amount Section 24(a) of the Internal Revenue Code of 1986 is amended by striking $1,000 and inserting $2,000 . (b) Limitation Paragraph (2) of section 24(b) of the Internal Revenue Code of 1986 is amended to read as follows: (2) Threshold amount For purposes of paragraph (1), the term threshold amount means— (A) $400,000 in the case of a joint return, and (B) $200,000 in any other case. . (c) Partial credit allowed for certain other dependents Subsection (h) of section 24 of the Internal Revenue Code of 1986 is amended to read as follows: (h) Partial credit allowed for certain other dependents (1) In general The credit determined under subsection (a) shall be increased by $500 for each dependent of the taxpayer (as defined in section 7706) other than a qualifying child described in subsection (c). (2) Exception for certain noncitizens Paragraph (1) shall not apply with respect to any individual who would not be a dependent if subparagraph (A) of section 7706(b)(3) were applied without regard to all that follows resident of the United States . (3) Certain qualifying children In the case of any qualifying child with respect to whom a credit is not allowed under this section by reason of subsection (e)(1), such child shall be treated as a dependent to whom subparagraph (A) applies. . (d) Maximum amount of refundable credit Subsection (d) of section 24 of the Internal Revenue Code of 1986 is amended by inserting after paragraph (3) the following new paragraph: (4) Limitation (A) In general The amount determined under paragraph (1)(A) with respect to any qualifying child shall not exceed $1,400, and such paragraph shall be applied without regard to subsection (h). (B) Adjustment for inflation In the case of a taxable year beginning after 2018, the $1,400 amount in subparagraph (A) shall be increased by an amount equal to— (i) such dollar amount, multiplied by