2024 Connecticut State Tax Deadlines

Connecticut Individual Income Tax Filing deadlines and extensions for 2024.

If you are a resident or have been involved in significant business operations within Connecticut, then you might be required to file Connecticut State Taxes. We explore the most crucial tax deadlines and tax extensions for Connecticut in 2024.

Connecticut Business Tax Deadline for 2024

C Corporation

Connecticut C Corporation Tax Deadlines for 2024

You must file & pay Corporate Income Taxes in Connecticut by May 15, 2025.

  • File Online with the Connecticut Department of Revenue Services.
  • File by Mail must be postmarked by the due date.

Form CT-1120 – Connecticut Corporation Business Tax Return

Extension to File Taxes in Connecticut for 2024

You must send payment for taxes in Connecticut for the fiscal year 2024 by May 15, 2025.

The Extension Deadline is November 15, 2025, to file your Connecticut corporate income tax return.

Connecticut automatically grants a 6-month extension for filing corporate income tax returns. This means you do not need to file for an extension in Connecticut.

This is an extension to FILE, not an extension to PAY – payment is still due May 15, 2025.

Pass-Throughs

Connecticut S Corporation & Partnership Tax Deadlines for 2024

You must file in Connecticut by March 15, 2025.

  • File Online with the Connecticut Department of Revenue Services.
  • File by Mail must be postmarked by the due date.

Forms:

  • CT-1065/CT-1120SI – Composite Income Tax Return for S Corporations and Partnerships
  • CT-1065 – Connecticut Partnership Income Tax Return

Extension to File S Corporation & Partnership Taxes in Connecticut for 2024

You must send payment for taxes in Connecticut for the fiscal year 2024 by March 15, 2025.

The Extension Deadline is September 15, 2025, to file your Connecticut S Corporation & Partnership income tax return.

Connecticut automatically grants a 6-month extension for filing pass-through entity tax returns. This means you do not need to file for an extension in Connecticut.

This is an extension to FILE, not an extension to PAY – payment is still due March 15, 2025.

Connecticut Individual Tax Deadline Section

Estimated Tax Deadline for Connecticut 2024

Estimated tax payments are made:

  • April 15, 2024,
  • June 17, 2024,
  • September 16, 2024,
  • January 15, 2025.

See Form CT-1040ES for the amount to pay with each voucher.

Individual Tax Deadline for Connecticut 2024

You must file & pay Individual Income Taxes in Connecticut by April 15, 2025.

  • File Online with the Connecticut Department of Revenue Services
  • File by Mail must be postmarked by the due date

Applicable forms:

  • Form CT-1040 – Connecticut Resident Income Tax Return
  • Form CT-1040NR/PY – Nonresident/Part-Year Resident Tax Return

Extension to File Taxes in Connecticut for 2024

You must send payment for taxes in Connecticut for the fiscal year 2024 by April 15, 2025.

The Extension Deadline is October 15, 2025, to file your Connecticut Individual Income tax return.

Connecticut automatically grants a 6-month extension for filing personal income taxes. This means you do not need to file for an extension in Connecticut.

This is an extension to FILE, not an extension to PAY – payment is still due April 15, 2025.

Sources

The material discussed on this page is meant for general illustration and/or informational purposes only and is not to be construed as investment, tax, or legal advice. You must exercise your own independent professional judgment, recognizing that advice should not be based on unreasonable factual or legal assumptions or unreasonably rely upon representations of the client or others. Further, any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.

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