2025 Form CT-6251

Connecticut Alternative Minimum Tax Return

Download or Print 2025 Connecticut Form CT-6251

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About Connecticut Form CT-6251

Connecticut Form CT-6251 is used to calculate Connecticut alternative minimum tax for an individual income tax return. The completed form attaches to the back of Form CT-1040 or Form CT-1040NR/PY when Connecticut DRS requires the alternative minimum tax calculation.

The 2025 Form CT-6251 PDF includes Part 1 for the Connecticut minimum tax calculation, Part 2 for taxpayers who must complete Part III of federal Form 6251, Schedule A for credit for alternative minimum tax paid to qualifying jurisdictions, a worksheet, general instructions, line item instructions, and Schedule A instructions.

Part 1 starts with federal alternative minimum taxable income and Connecticut additions or subtractions. Part 2 helps complete the adjusted federal tentative minimum tax calculation when that section applies. Schedule A is used by eligible residents and part-year residents to claim credit for alternative minimum tax paid to qualifying jurisdictions.

Connecticut Form CT-6251 PDF Files by Year

Click any of the Connecticut Form CT-6251 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.

Need more state income tax forms? View the full 2025 Connecticut income tax forms list.

Form CodeForm Name
Form CT-1040Connecticut Resident Income Tax Return
Form CT-1040NR/PYConnecticut Nonresident and Part-Year Resident Income Tax Return
CT-1040 TCSConnecticut Tax Calculation Schedule
Form CT-1040XAmended Connecticut Income Tax Return for Individuals

Frequently Asked Questions (FAQ)

Here are answers to common questions about downloading, printing, completing, and filing 2025 Connecticut Form CT-6251.

When is 2025 Connecticut Form CT-6251 due?

Form CT-6251 is filed with your Connecticut individual 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 Connecticut 1040 instructions, but pay any tax due by the original deadline to avoid penalties and interest.

What is Connecticut Form CT-6251 used for?

Use Form CT-6251 to calculate Connecticut alternative minimum tax when the form applies to your filing situation. The calculation uses federal alternative minimum tax information along with Connecticut additions, subtractions, exemptions, credits, and tax lines.

Who should use Form CT-6251?

Use Form CT-6251 if you are required to calculate Connecticut alternative minimum tax for a resident, part-year resident, or nonresident individual income tax return. The form instructions say taxpayers who do not have a federal alternative minimum tax liability are not required to complete Form CT-6251.

Do I attach Form CT-6251 to my Connecticut return?

Yes. Attach completed Form CT-6251 to the back of Form CT-1040 or Form CT-1040NR/PY when the form is required. Connecticut DRS says not to use staples when attaching the form.

What is included in the Form CT-6251 PDF?

The Form CT-6251 PDF includes Part 1, Part 2, Schedule A, a worksheet, general instructions, line item instructions, and Schedule A instructions. Schedule A is used to claim credit for alternative minimum tax paid to qualifying jurisdictions when that credit applies.

Where can I find the Form CT-6251 instructions?

The Form CT-6251 PDF includes the instructions for completing the Connecticut alternative minimum tax return. Also review the Form CT-1040 instructions or Form CT-1040NR/PY instructions for return-specific guidance.

Last updated: August 1, 2026

Connecticut Tax Forms

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