Perhaps this will help:
From the instructions for Illinois Schedule CR, line 51:
Line 51 – Follow the instructions on the form. Enter the total tax
you paid to all other states (including tax paid to cities or other local
government) minus all credits allowed, except credits for payments
you actually made to the other states or payments made on your
behalf. For full-year residents, you would report 100% of the taxes
paid.
For a part-year resident, include only the tax on income earned
or received while an Illinois resident. For example, you and your
spouse moved to Illinois from Indiana at the beginning of April. You
worked in Indiana the entire year, earning $30,000 in wages evenly
throughout the year. Your spouse worked in Indiana the entire year,
earning $24,000 in wages evenly throughout the year. Of your total
wage income, $40,500 of such income was earned during the
period you were an Illinois resident. Your only source of income
taxable in Indiana is your $54,000 of wage income. You paid
$1,000 in income tax to Indiana. The amount of Indiana tax you may
include on Line 51 is determined as follows:
$1,000 × ($40,500 /$54000)= $750.
Also, you may want to review this TT thread from 2021: The user was in a similar situation.
https://ttlc.intuit.com/community/state-taxes/discussion/i-moved-to-il-from-nyc-i-m-encountering-err....
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
