2025 Schedule CT-SI
Connecticut Source Income Schedule for Nonresidents and Part-Year Residents
Download or Print 2025 Connecticut Schedule CT-SI
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About Connecticut Schedule CT-SI
Connecticut Schedule CT-SI is used by nonresidents and part-year residents to report income from Connecticut sources. Use this schedule when you file Form CT-1040NR/PY and need to show the Connecticut portion of your wages, business income, rental income, capital gains, or other income items.
Schedule CT-SI works with the Connecticut nonresident and part-year resident return. Use the Form CT-1040NR/PY instructions to determine which lines apply, how Connecticut-source income is reported, and whether other allocation forms are required.
Connecticut Schedule CT-SI PDF Files by Year
Click any of the Connecticut Schedule CT-SI PDF links above to download, save, view, and print the file for the corresponding year. These free PDF files are unaltered and are sourced directly from the publisher.
Related Connecticut Part-Year and Nonresident Tax Forms
Need to download more state income tax forms? View the 2025 Connecticut part-year resident tax forms or nonresident tax forms lists.
| Form Code | Form Name |
|---|---|
| Form CT-1040NR/PY | Connecticut Nonresident and Part-Year Resident Income Tax Return |
| Form CT-1040NR/PY Instructions | Form CT-1040NR/PY Instruction Booklet |
| Schedule CT-1040AW | Part-Year Resident Income Allocation |
| Schedule CT-IT Credit | Income Tax Credit Summary |
Frequently Asked Questions (FAQ)
Here are answers to common questions about downloading, printing, completing, and attaching 2025 Connecticut Schedule CT-SI.
When is 2025 Connecticut Schedule CT-SI due?
Schedule CT-SI is filed with your Connecticut nonresident or part-year resident income tax return, so use the due date for the return you attach it to. For most 2025 Connecticut individual income tax returns, the due date is April 15, 2026. If you need more time to file, review the extension rules in the Form CT-1040NR/PY instructions, but pay any tax due by the original deadline to avoid penalties and interest.
Who should use Connecticut Schedule CT-SI?
Use Schedule CT-SI if you are a Connecticut nonresident or part-year resident and need to report income from Connecticut sources on Form CT-1040NR/PY. Full-year Connecticut residents generally use Form CT-1040 instead.
Where do I attach Schedule CT-SI?
Attach completed Schedule CT-SI to Form CT-1040NR/PY when the return or instructions require the Connecticut source income schedule. Review the CT-1040NR/PY line instructions before filing so you include the correct supporting forms.
Where can I find the Schedule CT-SI instructions?
Schedule CT-SI is explained in the Form CT-1040NR/PY instructions. Use those instructions to determine how to report Connecticut-source income and whether Schedule CT-1040AW or other supporting schedules apply.
Is Schedule CT-SI the same as Schedule CT-1040AW?
No. Schedule CT-SI reports income from Connecticut sources for nonresidents and part-year residents. Schedule CT-1040AW is a separate allocation schedule used by some part-year residents.
Last updated: August 1, 2026
References:
- Schedule CT-SI Connecticut Source Income Schedule for Nonresidents and Part-Year Residents. State of Connecticut, Connecticut Department of Revenue. Retrieved August 1, 2026.
- Form CT-1040NR/PY Connecticut Nonresident and Part-Year Resident Income Tax Return Instructions. State of Connecticut, Connecticut Department of Revenue. Retrieved August 1, 2026.
- Individual Income Tax Forms. State of Connecticut, Connecticut Department of Revenue. Retrieved August 1, 2026.
- Connecticut Nonresident and Part-Year Resident Tax Information. State of Connecticut, Connecticut Department of Revenue. Retrieved August 1, 2026.