Taxable income—Standard deduction—Index for inflation.

(1) Beginning October 2029 and each October of an odd-numbered year thereafter, the department must adjust the standard deduction under RCW 82A.04.360 by multiplying the current standard deduction amount by one plus the percentage by which the most current consumer price index available on October 1st of the current year exceeds the consumer price index for the prior 12-month period, and rounding the result to the nearest $1,000. If an adjustment under this subsection (1) would reduce the standard deduction amount, the department must not adjust the amounts for use in the following year. The department must publish the adjusted standard deduction amount on its public website by October 31st of each year. The adjusted standard deduction amount calculated under this subsection (1) takes effect for taxes due in the following calendar year.(2) For purposes of this section, "consumer price index" means the consumer price index for all urban wage earners and clerical workers as calculated by the United States bureau of labor statistics or its successor agency.[ 2026 c 238 s 316.]Notes:Findings—Intent—Effect of invalidation of 2026 c 238 s 201—Automatic expiration date and tax preference performance statement exemption—Necessity of act—Intent—Implementation by department of revenue—2026 c 238: See notes following RCW 82A.04.030.