15-30-2132. Standard deduction. (1) A standard deduction equal to 20% of adjusted gross income is allowed if elected by the taxpayer on a return. The standard deduction is in lieu of all deductions allowed under 15-30-2131. The minimum standard deduction is $1,980, as adjusted under the provisions of subsection (2), or 20% of adjusted gross income, whichever is greater, to a maximum standard deduction of $4,460, as adjusted under the provisions of subsection (2). However, in the case of a single joint return of husband and wife or in the case of a single individual who qualifies to file as a head of household on the federal income tax return, the minimum standard deduction is twice the amount of the minimum standard deduction for a single return, as adjusted under the provisions of subsection (2), or 20% of adjusted gross income, whichever is greater, to a maximum standard deduction of twice the amount of the maximum standard deduction for a single return, as adjusted under the provisions of subsection (2). The standard deduction may not be allowed to either the husband or the wife if the tax of one of the spouses is determined without regard to the standard deduction. For purposes of this section, the determination of whether an individual is married must be made as of the last day of the tax year unless one of the spouses dies during the tax year, in which case the determination must be made as of the date of death.

(2) By November 1 of each year, the department shall multiply both the minimum and the maximum standard deduction for single returns by the inflation factor for the following tax year and round the product to the nearest $10. The resulting adjusted deductions are effective for that following tax year and must be used in calculating the tax imposed in 15-30-2103.