IDAPA 35.01.01.255 — NONRESIDENT AND

PART-YEAR
RESIDENT
INDIVIDUALS
--
PRORATION
OF
EXEMPTIONS AND DEDUCTIONS (RULE 255).
Section 63-3026A(4), Idaho Code
01.
In General. The exemptions and deductions allowable for federal purposes, except for the
deduction of state and local income taxes and the deduction for state and local general sales taxes, are allowed in part
in computing Idaho taxable income. To determine the portion of exemptions and deductions allowable for part-year
and nonresident individuals, the total exemptions and deductions allowed by Section 151, Internal Revenue Code,
and Section 63-3022(j), Idaho Code, are multiplied by the calculated proration.
(4-6-23)
02.
Proration. For taxable years beginning in or after 2007, the proration is calculated by dividing
Idaho adjusted income by total adjusted income. Calculate four (4) digits to the right of the decimal point. If the fifth
digit is five (5) or greater, the fourth digit is rounded to the next higher number ($10,000 / $15,000 = .66666 = .6667
= 66.67%). If the fifth digit is less than five (5), the fourth digit remains unchanged and any digits remaining to its
right are dropped ($10/000 / $30,000 = .33333 = .3333 = 33.33%). The percentage may not exceed one hundred
percent (100%), nor be less than zero (0).
(4-6-23)
IDAHO ADMINISTRATIVE CODE
IDAPA 35.01.01
Idaho State Tax Commission
Income Tax Administrative Rules
Section 256
Page 36
a.
Idaho adjusted income means the Idaho taxable income of the taxpayer as computed pursuant to
Title 63, Chapter 30, Idaho Code, except for any adjustments for the standard deduction or itemized deductions and
personal exemptions. Total adjusted income means the Idaho taxable income of the taxpayer computed as if he were a
resident of Idaho for the entire taxable year, except no adjustments are made for the standard deduction, itemized
deductions, personal exemptions, the deduction for active military service pay as provided in Section 63-3022(h),
Idaho Code, and any deduction for income earned within a federally recognized Indian reservation.
(4-6-23)
b.
Generally, both Idaho adjusted income and total adjusted income are positive amounts. If Idaho
adjusted income is less than or equal to the total adjusted income, the percentage is between zero (0) and one hundred
percent (100%). If Idaho adjusted income is greater than the total adjusted income, the percentage is one hundred
percent (100%). If Idaho adjusted income is a positive amount and total adjusted income is a negative amount, the
percentage is one hundred percent (100%). If Idaho adjusted income is a negative amount and total adjusted income
is a positive amount, the percentage is zero (0).
(4-6-23)
03.
Standard Deduction for Married Filing Joint Returns. The proration percentage is applied after
making the following calculations for taxable years beginning on or after January 1, 2000. The standard deduction
allowed on a married filing joint return is equal to two (2) times the basic standard deduction for a single individual.
Add to this amount any additional standard deduction for the aged or blind allowed for federal income tax purposes.
(4-6-23)