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

Form CT-1040 EXT

Department of Revenue Services

State of Connecticut
Application for Extension of Time to File
(Rev. 12/25)

Connecticut Income Tax Return for Individuals

# 1040EXT 1225 W 01 9999

See the instructions on the back before completing this form. Complete this form in blue or black ink only.
Type or print. Please note that each form is year specific. To prevent any delay in processing your return, the correct Important! year's form must be submitted to the Department of Revenue Services (DRS). Do not use staples. You must enter your complete SSN(s) below.
Your first name Middle initial Last name Suffix (Jr./Sr.) Your Social Security Number (SSN)      If joint return, spouse's first name Middle initial Last name Suffix (Jr./Sr.) Spouse's SSN      Home address (number and street), apartment number, PO Box Daytime telephone number  City, town, or post office State ZIP code Country code    
This is not an extension of time to pay your tax.

To request an extension of time to pay, file Form CT-1127,

Application for Extension of Time for Payment of Income Tax.
You must file this form by the due date of your original return or your request will be denied. See instructions. However, if you expect to owe no additional Connecticut income tax for the 2025 taxable year, after taking into account any Connecticut income tax withheld from your wages, any estimated Connecticut income tax payments you have made, and any Pass-Through Entity Tax Credit, and you have requested an extension of time to file your 2025 federal income tax return, you are not required to file Form CT‑1040 EXT. You will be subject to interest and may be subject to a penalty on any amount of tax not paid on or before the original due date of your return.
I request a six-month extension of time to October 15, 2026, to file my Connecticut income tax return for the year beginning January 1, 2025, and ending December 31, 2025. If you are not a calendar year taxpayer, complete the following:
My six-month extension of time is to: (MM-DD-YYYY) My tax year begins (MM-DD-YYYY) and ends:  (MM-DD-YYYY) I have requested a federal extension on federal Form 4868, Application for Automatic Extension of Time to File U.S.
Individual Income Tax Return, for taxable year 2025. If you have not filed for a federal extension, explain why you Check are requesting the Connecticut extension: here
You will be notified only if your extension request is denied.

1. Total income tax liability for 2025. You must enter an amount on Line 1. If you do not expect to owe income tax, enter "0." … 1. .00
2. Total individual use tax liability for 2025. You must enter an amount on Line 2. If you

.00 do not expect to owe use tax, enter "0." … 2.

1. Add Line 1 and Line 2 … 3. .00
2. Connecticut income tax withheld: Do not attach W-2s or 1099s … 4. .00
3. 2025 estimated Connecticut income tax payments including any

2024 overpayments applied to 2025 … 5. .00
5a. 2025 Pass-Through Entity Tax Credit … 5a. .00 .00

1. Add Lines 4, 5, and 5a … 6.
2. Connecticut income tax and use tax due: Subtract Line 6 from Line 3.

If Line 6 is greater than Line 3, enter "0." Amount due with this form: …  7. .00 Forms with payment, mail to: Forms without payment:

# Department of Revenue Services

PO Box 2977 PO Box 2976

Hartford CT 06104-2977 Hartford CT 06104-2976 Make your check payable to: Commissioner of Revenue Services Do not mail this return if you do not owe any tax and you have requested an extension of To ensure proper posting, write your SSN (optional) and "2025 Form CT‑1040 EXT" on your check. time to file your 2025 federal income tax return.
Visit us at portal.ct.gov/DRS for more information.

Department of Revenue Services

Form CT-1040 EXT Instructions

# State of Connecticut

Form CT‑1040 EXT only extends the time to file your Connecticut income tax return. Form CT‑1040 EXT does not extend the time to pay your income tax. You must pay the amount of tax that you expect to owe on or before the original due date of the return. See Interest and Penalty.
You may qualify for a six-month extension of time to pay your tax. To request this extension, you must file Form CT‑1127, Application for Extension of Time for Payment of Income Tax, with your timely filed Connecticut income tax return or extension.
Purpose: Use Form CT‑1040 EXT to request a six‑month extension to file your Connecticut income tax return for individuals. This form also extends the time to file your individual use tax. It is not necessary to include a reason for the Connecticut extension request if you have already filed an extension request on federal Form 4868 with the Internal Revenue Service. If you did not file federal Form 4868, you can apply for a six‑month extension to file your Connecticut income tax return provided you have good cause for your request.
Exception: If you expect to owe no additional Connecticut income tax for the 2025 taxable year, after taking into account any Connecticut income tax withheld from your wages, any estimated Connecticut income tax payments you have made, and any Pass‑Through Entity Tax Credit, and you have requested an extension of time to file your 2025 federal income tax return, you are not required to file Form CT‑1040 EXT. DRS will automatically grant you a six-month extension of time to file your 2025 Connecticut income tax return. If you did not request an extension of time to file your federal income tax return, but you are requesting an extension of time to file your Connecticut income tax return, you must file Form CT‑1040 EXT whether or not you owe additional Connecticut income tax.

# Electronically File Form CT‑1040 EXT

Form CT‑1040 EXT can be filed and paid electronically using myconneCT.
DRS myconneCT allows Connecticut income tax filers to electronically file, pay and manage state tax responsibilities.
How to Get an Extension to File
To obtain a Connecticut extension of time to file if the exception above does not apply, you must:

• Complete Form CT‑1040 EXT in its entirety;
• File it on or before the due date of your return; and
• Pay the amount shown on Line 7.

Any payment made with this form is considered an income tax payment regardless of the amounts you enter on Line 1 and Line 2. Your signature is not required on this form. DRS will notify you only if your request is denied.

# U.S. Citizens or Residents Who Are Out of the Country

You must file this form if you qualify as a taxpayer who is out of the country for purposes of filing your federal return. Generally, you are out of the country if you are:

• A U.S. citizen or resident living outside the U.S. and Puerto Rico and your main place of work is outside the U.S. and Puerto Rico; or
• In the military or naval service on duty outside the U.S. and Puerto Rico on the date your federal income tax return is due and are unable to file a timely Connecticut income tax return.

Explain on the front of this form that you are a U.S. citizen or resident outside of the country and that you qualify for the automatic, two‑month federal income tax extension.
If your application is approved, the due date for filing your Connecticut return will be extended for six months (October 15, 2026, for calendar year taxpayers). If you are still unable to file your Connecticut Form CT-1040 EXT Back (Rev. 12/25) return by the extended due date and you have applied for and were granted an extension of time to file for federal purposes using federal Form 2350, you must file your Connecticut return using the federal extension due date. You must attach a copy of the federal Form 2350 approval notice to the front of your Connecticut return.

# When to File Form CT-1040 EXT

File Form CT‑1040 EXT on or before April 15, 2026. If your taxable year is other than the calendar year, file Form CT‑1040 EXT on or before the fifteenth day of the fourth month following the close of your taxable year. If the due date falls on a Saturday, Sunday, or legal holiday, your extension request will be considered timely if filed on the next business day.

# Payment Options

Pay Electronically: This option is only available if you file Form CT‑1040 EXT electronically and make a payment electronically on the DRS website through myconneCT. You can file your return any time before the due date and designate the amount of payment and date of transfer.
Your bank account will be debited on the date you indicate. You must pay the balance due on or before April 15, 2026, to avoid penalty and interest.
Pay by Credit Card or Debit Card: You may elect to pay your expected 2025 tax liability using a credit card (American Express®, Discover®, Master Card®, Visa®) or comparable debit card. A convenience fee will be charged by the credit card service provider. Your payment will be effective on the date you make the charge.
At the end of the transaction, you will receive a confirmation number for your records. As a reminder, even if you pay electronically, you must still file your return by the due date. Tax not paid on or before the due date will be subject to penalty and interest.
Do not send in Form CT‑1040 EXT if you make your payment by credit card. All credit card payments for extension requests will be accepted by the credit card service provider. However, if your payment is late, DRS will notify you in writing that your request is denied.
Pay by Mail: Make your check payable to Commissioner of Revenue Services. To ensure proper posting of your payment, write "2025 Form CT‑1040 EXT" and your Social Security Number(s) (optional) on the front of your check. Be sure to sign your check and paper clip it to the front of your return. Do not send cash. DRS may submit your check to your bank electronically.

# Interest and Penalty

In general, interest and penalty apply to any portion of the tax not paid on or before the original due date of the return. Interest is computed on the underpayment of tax at 1% per month or fraction of a month computed from the original due date to the date of payment.
Late Payment Penalty: The penalty for underpayment of tax is 10% of the tax that is not paid on or before the original due date of the return.
Late Filing Penalty: If no tax is due, DRS may impose a $50 penalty for the late filing of any return or report that is required by law to be filed.

# Line Instructions

Line 1: Enter the amount that you expect to enter on:

Form CT‑1040, Line 14, or Form CT‑1040NR/PY, Line 16.
Line 2: Enter the amount that you expect to enter on:

Form CT‑1040, Line 15, or Form CT‑1040NR/PY, Line 17.
Line 4: Enter the amount that you expect to enter on:

Form CT‑1040, Line 18, or Form CT‑1040NR/PY, Line 20.
Line 5: Enter the amount that you expect to enter on:

Form CT‑1040, Line 19, or Form CT‑1040NR/PY, Line 21.
Line 5a: Enter the amount that you expect to enter on:

Form CT‑1040, Line 20c or Form CT‑1040NR/PY, Line 22b.