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How to File a Connecticut State Tax Amendment

Connecticut State Taxes
amend Connecticut taxes
Connecticut
"The Constitution State"

When Should I Complete and File My Amended Connecticut Tax Return?

You must prepare and file your Connecticut amended tax return within 3 years of the filing deadline (your original or extended deadline), whichever is earlier.

However, if one of the following situations apply to you, you must file your amended Connecticut tax return within 90 days:

  • The IRS or a federal court makes changes to your federal income that affect your Connecticut state income tax return.
  • You filed a federal tax amendment form and it affected your Connecticut state income tax.
  • You claimed a tax credit in your original federal tax return and either you, a tax official, or a court made a change in your tax return that also affects your Connecticut income tax return

How Do I Fix My Accepted Connecticut Tax Return or File a Tax Amendment in Connecticut?

You need to file an amended Connecticut tax form in order to correct your original, accepted Connecticut tax return. Here's how:

  1. Download and complete Form CT 1040X.
  2. Mail the tax amendment to this address: Department of Revenue Services, PO Box 2978, Hartford, CT 06104-2978.

Connecticut State Tax Amendment Forms (Download, Print Out, Fill Out, and Mail)

Fill out Form CT 1040-X for the appropriate Tax Year.

Form (Tax Year) Description
Form CT 1040X (2016) Amended Connecticut Income Tax Return for Individuals
Form CT 1040X (2015) Amended Connecticut Income Tax Return for Individuals
Form CT 1040X (2014) Amended Connecticut Income Tax Return for Individuals
Form CT 1040X (2013) Amended Connecticut Income Tax Return for Individuals
Form CT 1040X (2012) Amended Connecticut Income Tax Return for Individuals
Form CT 1040X (2011) Amended Connecticut Income Tax Return for Individuals

How Do I Check the Status of My Connecticut State Tax Amendment?

You can call the CT Department of Revenue Services at 860-297-5962.

What Are the Penalties, Interest, and Fees Related to Amended Connecticut Tax Returns?

Any outstanding tax balance paid after the original tax return deadline is usually subject to a 10% penalty. There is also a 1% interest rate for each month or fraction of a month until the payment is made.

If you didn't pay enough income tax then you can use form CT 2210 - Underpayment of Estimated Income Tax by Individuals, Trusts, Estates to estimate the interest that's due.

Where Do I Mail My Connecticut Amended Tax Return? - Connecticut Mailing Address:

Department of Revenue Services,
PO Box 2978, Hartford, CT 06104-2978

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

Department of Revenue Services Phone Number: 860-297-5962

Department of Revenue Services

Where Do I Learn More About Income Taxes in Connecticut?

How Do I Just Prepare, File My Connecticut Tax Return?

Where is my Connecticut State Tax Refund?

How to File a Connecticut Income Tax Extension

Connecticut Tax Information

What If I Need to Prepare and File My Federal Amended Tax Return?

Learn how to file an IRS income tax amendment.