; (2) in subclause (II) of subsection (c)(1)(A)(ii), by striking attained age 25 but not attained age 65 and inserting attained age 21 but not attained age 67 ; and (3) by amending subsection (j) to read as follows: (j) Inflation adjustments (1) In general In the case of any taxable year beginning after 2017, each of the dollar amounts in subparagraph (A) of subsection (b)(2) (after being increased under subparagraph (B) thereof) 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, determined by substituting calendar year 2016 for calendar year 1992 in subparagraph (B) thereof. (2) Rounding If any dollar amount increased under paragraph (1) is not a multiple of $50, such dollar amount shall be rounded to the nearest multiple of $50. . (b) Effective date The amendments made by this section shall apply to taxable years beginning after December 31, 2016. 202. Establishment of fully refundable child tax credit (a) Credit made refundable (1) In general The Internal Revenue Code of 1986 is amended— (A) by redesignating section 24 as section 36C