Updated October 24, 2026. Quick answer: Line 15 of the 2025 Illinois IL-1040 is the credit for income tax paid to another state. The instructions say “If you were taxed by another state on income you received while you were an Illinois resident, you may be entitled to this credit.” It is not a subtraction. The Schedule M instructions say “No, you may not subtract your out-of-state income.”
What this line asks
On the form the line reads income tax paid to another state while an Illinois resident, with an attachment of Schedule CR. The instructions open: “If you were taxed by another state on income you received while you were an Illinois resident, you may be entitled to this credit.”
This line sits in Step 6 of the return, among the nonrefundable credits. For the other lines, see the Illinois IL-1040 line by line guide.
Who it applies to
The heading on the instructions limits the line to Illinois residents and part-year residents. The Schedule M instructions repeat the idea in their opening questions: “if you are filing as a resident or a part-year resident, you may be allowed to take a credit against Illinois Income Tax for income tax you paid to another state.”
The Schedule M instructions also answer the question of whether out-of-state income can come out of income first: “No, you may not subtract your out-of-state income.” Retirees who moved during the year, or who receive income taxed by another state, can read out-of-state pensions in Illinois and leaving Illinois and retirement taxes.
What the instructions say to enter
| Step | What the instructions say |
|---|---|
| Possible credit | “you may be entitled to this credit.” |
| Where to check eligibility | “See the Schedule CR Instructions and Publication 111, Illinois Schedule CR for Individuals, to see if you are eligible to take this credit.” |
| Attachment | “Attach: Schedule CR, Pages 1 through 3.” |
| Out-of-state income is not subtracted | “No, you may not subtract your out-of-state income.” |
| Credit instead | “you may be allowed to take a credit against Illinois Income Tax for income tax you paid to another state.” |
The figures the line prints
The line 15 instructions print no dollar, percentage or age limit of their own. They send you to Schedule CR and Publication 111 to work out the credit. Line 16 and line 17 are printed next to it, with a combined limit that the instructions state in one sentence: “Form IL-1040, Line 15 + Line 16 + Line 17 cannot be greater than Line 14.”
Where the result goes next
The form adds the three credit lines together. Line 18 reads “Add Lines 15, 16, and 17.” Line 19 on the form reads “Subtract Line 18 from Line 14.” For the types of income people most often ask about, see Illinois tax on dividends and interest and Illinois tax on capital gains.
Edition and line numbers
This page reads the 2025 Form IL-1040 Instructions from the Illinois Department of Revenue, the current file served on 2026-10-24. Check the edition printed on your own form and use that edition’s line numbers.
Common mistakes
- Trying to subtract income earned in another state on Schedule M. The Schedule M instructions say “No, you may not subtract your out-of-state income.”
- Sending the return without the credit schedule. The instructions say “Attach: Schedule CR, Pages 1 through 3.”
- Letting lines 15 to 17 add up to more than the tax. The instructions say “Form IL-1040, Line 15 + Line 16 + Line 17 cannot be greater than Line 14.”
Related: Illinois retirement taxes, out-of-state pensions in Illinois, leaving Illinois and retirement taxes, Illinois tax on dividends and interest, and Illinois tax on capital gains.
Find the right next step for your situation
About how much do you have invested? Pick the range that fits; your next step appears immediately below.
Talk to an advisor about retirement tax planning
For U.S. investors with $250,000 or more in investable assets. WiserAdvisor is an independent service matching you with 2 to 3 vetted advisers. Its form asks for your ZIP code and answers to a few questions; a match is not guaranteed.
Free to request, with no obligation to hire. By submitting, you consent to calls, texts and emails from WiserAdvisor and up to three advisers. Advisers pay for introductions.
Clear Money Guide may earn a referral payment for a qualifying completed form. An introduction is not a Clear Money Guide recommendation.
Opens on WiserAdvisor’s site in a new tab.
Explore advisor help with multi state retirement taxes
Price the destination before you decide. The matching service below introduces you to advisers who pay to meet you.
Before you start, what actually happens. The form is run by Kapitalwise, our advisor-matching partner. Kapitalwise sends your details to advisers who pay for the introduction, so expect calls and texts. Clear Money Guide may earn a referral payment for a qualifying submitted form, whether or not you ever hire anyone. This is free to you and there is no obligation to hire anyone.
The Kapitalwise form opens here; you stay on this page.
What happens when you press the button
It asks about nine questions: age, investable assets, location; then your name, email and phone number, and verifies the phone by text. Nothing loads and nothing reaches Kapitalwise until you press the button.
Prefer flat-fee or hourly pricing instead? Compare ranges here.
Answer againSources
- 2025 Form IL-1040 Instructions, Illinois Department of Revenue: tax.illinois.gov
- 2025 Schedule M Instructions (Other Additions and Subtractions for Individuals), Illinois Department of Revenue: tax.illinois.gov
- 2025 Form IL-1040 Individual Income Tax Return, Illinois Department of Revenue: tax.illinois.gov
Read from the state revenue documents linked above on October 24, 2026. General information, not tax advice. Your own facts decide the outcome, and a preparer or the state revenue department is the right place to confirm anything consequential.