CT-1040 EXT: Application for Extension of Time to File Connecticut Income Tax Return for Individuals (2024)
Connecticut · Connecticut DRS · Used for tax years 2024
Form CT-1040 EXT requests a six-month extension to file your 2024 Connecticut individual income tax return and individual use tax. It reports expected tax liabilities, withholding, estimated payments, the Pass-Through Entity Tax Credit, and any amount due. It extends the time to
Who files this form
Use Form CT-1040 EXT to request a six-month extension to file your Connecticut individual income tax return. It also extends the time to file your individual use tax.
- If you requested a federal extension for 2024 and expect to owe no additional Connecticut income tax after withholding, estimated payments, and any Pass-Through Entity Tax Credit, you do not need to file this form. DRS automatically grants a six-month filing extension.
- If you did not request a federal extension but want a Connecticut extension, you must file this form whether or not you owe additional Connecticut income tax. You must explain the good cause for your request.
- If you qualify as an out-of-country taxpayer for federal filing purposes, the instructions say you must file this form. Explain that you are a U.S. citizen or resident outside the country and qualify for the automatic two-month federal extension.
When it's due
For tax year 2024 calendar-year taxpayers:
- April 15, 2025: File Form CT-1040 EXT and pay the balance due to avoid penalty and interest.
- October 15, 2025: Extended deadline to file the 2024 Connecticut income tax return.
This extension gives you more time to file, not more time to pay.
What you'll need
Have the following information ready:
- Your name, complete Social Security number, address, and daytime telephone number. Include your spouse’s name and complete Social Security number for a joint return.
- Your expected 2024 Connecticut income tax and individual use tax liabilities.
- Your Connecticut income tax withholding and 2024 estimated payments, including any 2023 overpayment applied to 2024.
- Your 2024 Pass-Through Entity Tax Credit, if any.
- Whether you requested a federal extension on Form 4868. If not, provide the reason for your Connecticut extension request.
- Your tax-year beginning and ending dates and requested extension date if you are not a calendar-year taxpayer.
Do not attach W-2s or 1099s.
How to file
Complete the form in full. For a paper form, type or print using blue or black ink. No signature is required on Form CT-1040 EXT.
Calculate the amount due
- Enter expected income tax on Line 1 and individual use tax on Line 2. Enter “0” on either line if you do not expect to owe that tax.
- Add Lines 1 and 2 on Line 3.
- Enter withholding on Line 4, estimated payments and applied overpayments on Line 5, and the Pass-Through Entity Tax Credit on Line 5a.
- Add Lines 4, 5, and 5a on Line 6.
- Subtract Line 6 from Line 3 and enter the result on Line 7. If Line 6 is greater than Line 3, enter “0.” Pay the amount on Line 7.
File and pay electronically
You can file and pay through DRS myconneCT. Information is available at portal.ct.gov/DRS. When filing and paying electronically through myconneCT, you can choose the payment amount and bank-account transfer date.
You may also pay by credit card or comparable debit card. A convenience fee applies, and you will receive a confirmation number. Do not send Form CT-1040 EXT if you make your payment by credit card.
Mail with payment
Department of Revenue Services
PO Box 2977
Hartford CT 06104-2977
Make your check payable to Commissioner of Revenue Services. Write “2024 Form CT-1040 EXT” on the check; adding your Social Security number(s) is optional. Sign the check and paper clip it to the front of the form. Do not send cash or use staples.
Mail without payment
Department of Revenue Services
PO Box 2976
Hartford CT 06104-2976
Do not mail the form if you owe no tax and have requested an extension to file your 2024 federal income tax return.
Common mistakes
- Treating this as extra time to pay. Form CT-1040 EXT extends only the filing deadline. Unpaid tax is subject to interest and may be subject to a penalty.
- Filing the extension request late. The form warns that a request filed after the original return due date will be denied.
- Leaving Lines 1 or 2 blank. You must enter an amount on both lines, even if it is “0.”
- Omitting complete Social Security numbers. Complete SSNs are required on the form, even though including them on your check is optional.
- Using the wrong year’s form. Submit the correct year’s form to avoid processing delays.
- Attaching W-2s or 1099s, using staples, or sending cash. The form says not to do these things.
- Assuming an electronic payment replaces filing your return. You must still file your income tax return by its due date.
Questions people ask
Does this form extend the time to pay my tax?
No. To request an extension of time to pay, file Form CT-1127 with your timely filed Connecticut income tax return or extension. You may qualify for a six-month payment extension.
Do I need to explain why I want an extension?
Not if you already requested a federal extension on Form 4868. If you did not, you must explain the good cause for your Connecticut extension request.
Will DRS confirm that my request was approved?
DRS will notify you only if your request is denied.
Do I need to sign Form CT-1040 EXT?
No. Your signature is not required on this form. If you pay by check, you must sign the check.
What if I am outside the country and have an approved federal Form 2350 extension?
If you are still unable to file by the extended Connecticut deadline and were granted a federal extension using Form 2350, file your Connecticut return using the federal extension due date. Attach a copy of the federal Form 2350 approval notice to the front of your Connecticut return.