How to File a Connecticut State Tax Amendment

amend Connecticut taxes
“The Constitution State“

If you need to change or amend an accepted Connecticut State Income Tax Return for the current or previous Tax Year you need to complete Form CT 1040X. Form CT 1040X is a Form used for the Tax Return and Tax Amendment. You can prepare a 2018 Connecticut Tax Amendment on, however you can not submit it electronically. In comparison, the IRS requires a different Form - Form 1040X -to amend an IRS return (do not use Form 1040 for an IRS Amendment).

The IRS might send you a notification to change an error on your Return, or you might have discovered an error. If you or the IRS amended or changed one of your IRS Tax Return(s), the IRS will report this to the Connecticut Tax Agency, thus you should file a Connecticut Tax Amendment within one year.

Prepare only a CT State Return
with a State Only Code: FreeFed19
File a 2018 Connecticut Tax Amendment
You cannot eFile an CT Tax Amendment anywhere, except mail it in. However, you can prepare it here on
Only Option: You will need to complete, sign CT Form CT 1040X for the appropriate Tax Year- Print, Mail the Form to CT Tax Department to:
Department of Revenue Services
P.O. Box 2935
Hartford, CT 06104-2935
If you owe money to the state of Connecticut after filling out your amended tax return and received a refund check that hasn't yet been deposited, mail your Connecticut amended return to
Attn: Accounts Receivable Unit
25 Sigourney Street, Ste. 2
Hartford, CT 06106
CT Tax Amendment Form 1040X
This Form can be used to file an: Income Tax Return, Tax Amendment, Change of Address. Check the proper check box on the Form.
Step 1: Select the CT Form 1040X by Tax Year below
Step 2: Sign, Mail CT Form 1040X to one of the addresses listed above
Tax Year 2018 only: Prepare online on until Oct. 15, 2019. When done Print, Sign and Mail in - not eFile - Your Tax Amendment, Address Change etc.
After Oct. 15 Prepare, Print, Sign and Mail-In - see address above - your Tax Year 2018 - Form CT 1040X
How to correct a rejected Tax Return
If your CT Tax Return was rejected by the CT Tax Agency - not - instructions on how to correct a rejected Connecticut Tax Return.
For all Tax Years prior to 2018 Prepare, Print, Sign and Mail-In - see address above - your Tax Amendment by Tax Year as soon as possible. You will also file an IRS Tax Amendment Form 1040X.
Check Your CT Tax Amendment Status
1. Call the Connecticut Department of Revenue Services at (860) 297-5962
2. Contact the CT Dep. of Revenue Services
Connecticut Refund Deadlines
A. Three years from the due date of the original tax year return, including valid filing extensions.
B. One year from the final determination of the amended federal return or federal change, whichever is later, provided that the allowable refund is not more than the decrease in Connecticut tax attributable to the federal change or correction.
C. Two years from the payment of an assessment, provided the amended return raises issues relating only to the prior assessment and the refund does not exceed the amount of tax paid on the prior assessment.
D. Two years from the filing of an amended Connecticut return resulting in the payment of additional tax, provided that the current amended return raises issues relating solely to the prior amended return and that the refund does not exceed the amount of the tax payment made as a result of the prior amended return.
Additional Connecticut Tax Income Taxes Deadlines
Connecticut Income Tax Penalties
Find out how Connecticut Late Filing and Late Payment Penalties are calculated.
For IRS Tax and Late Filing Penalties we have an easy to use tool: The PENALTYucator.
File an IRS Tax Amendment by Tax Year
Instructions on how to prepare an IRS Tax Amendment on, however the IRS does not accept Tax Amendments electronically.