Filing Connecticut Income Taxes

Since 2011, the Connecticut income tax rate has varied between 3 and 6.5%. Presently, the annual tax revenue for the state is over $15 billion, which is close to the median range in America. Residents, nonresidents and partial-year residents of Connecticut, who earn money within the state must file an annual income tax return. Residents should use the form CT 1040, nonresidents and partial-year residents should use the form CT 1040NR/PY.

Connecticut taxes are due April 15th. Any outstanding amount after this date is subject to a 10% penalty along with an additional 1% fee each month for as long as the amount remains unpaid. If the 10% fee is less than $50, the fee is adjusted to the minimum fee amount of $50.

Asking for an Extension

Requesting an extension of time to file (form CT 1040EXT) can be sent to this address, depending upon whether a Connecticut tax refund is expected or tax payment is due: 

Residents mailing forms with payments should send them to:

PO BOX 2977

Hartford CT 06104-2977

Estimated Payments and Amendments

If estimated payments are necessary, they can be paid online at, or by mail to the DRS. When paying by mail, send vouchers and payments to:

PO Box 2932

Hartford CT 06104-2932

If an error is discovered and an amendment is needed, taxpayers may use the form CT 1040X and mail it to:

PO Box 2978

Hartford, CT 06104-2978

For questions on amended returns or its status, you may call 860-297-5962

How Do I Track My Refund?

To track your Connecticut refund, you may visit On the left side of the menu, mouse over "How Do I" and click the option to check the status of a refund.

Note: States & U.S. territories may make changes to their tax laws with little notice. We do our best to keep this information up-to-date, but it is provided on an "AS IS" basis. For more see our terms.