Connecticut Personal Tax Extension | Form CT-1040 EXT | Application for Extension of Time to File Connecticut Income Tax Return for Individuals

Connecticut Personal Tax Extension Guide 

Connecticut’s Automatic Extension with Federal Approval

The Connecticut Department of Revenue Services (DRS) aligns with the federal tax extension system. If you’ve received an extension from the IRS by filing Form 4868, you are automatically granted a six-month extension to file your Connecticut state tax return. Your new extended due date becomes October 15, 2025.

Important Caveats on Payment Obligations

Although Connecticut honors the federal extension for filing, it does not grant more time to pay. Interest will be charged on unpaid tax after April 15, 2025, and penalties may apply. Estimate your tax liability and submit payment before the deadline to avoid charges.

How to Make Extension Payments

Connecticut offers several payment methods:

• Credit Card: Use www.acipayonline.com and select “state payments.” A convenience fee applies.
• ACH Debit: Pay via the Taxpayer Service Center at portal.ct.gov/TSC, or go to drsindtax.ct.gov for no-login payments.

Using Form CT-1040 EXT

To pay by mail, use Form CT-1040 EXT. It ensures your payment is credited properly. You must still file your return by October 15, 2025.

Mailing Addresses for Extension Payments

• No PaymentDepartment of Revenue Services
  P.O. Box 2976
  Hartford, CT 06104-2976

• With Payment:Department of Revenue Services
  P.O. Box 2977
  Hartford, CT 06104-2977

Late Payment and Filing Penalties

A penalty of the greater of $50 or 10% of unpaid tax applies for failing to file. A 10% penalty applies for late payment. Interest is charged from the original due date.

Best Practices

• Pay as much as you can by April 15 to reduce charges.
• Use secure online portals for confirmation.
• Save confirmation numbers and payment records.

Final Thoughts

By aligning with the IRS, Connecticut simplifies the extension process. However, payment is still due on time. File accurately, pay promptly, and use digital tools for the smoothest experience.