Filing Connecticut Income Taxes

Connecticut State Map

Since 2011, the Connecticut income tax rate has varied between 3 and 6.99%. Currently, the state's annual tax revenue exceeds $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.

The state's 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.

Who Must File Connecticut Taxes

You must file a Connecticut income tax return if your gross income exceeds certain thresholds by filing status:

  • $15,000 for single filers
  • $19,000 for head of household
  • $12,000 for married filing separately
  • $24,000 for married filing jointly

These income thresholds help determine whether you're required to file a state return, regardless of whether you owe taxes.

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

Connecticut Tax Rates and Brackets

Connecticut uses graduated tax rates from 3% to 6.99%, varying by income and filing status. The state also imposes a top 7.5% corporate income tax rate for businesses.

The state has a 6.35% sales tax rate with no additional local sales taxes, creating a simpler structure than many other states that add local taxes on top of state rates.

Estimated Payments and Amendments

If estimated payments are necessary, they can be paid online at drsindtax.ct.gov/AUT/welcomeindividual.aspx, 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 their status, you may call 860-297-5962

Tax Benefits for Residents

Connecticut provides several tax exemptions that can reduce your tax burden:

  • Social Security benefits are exempt from state income tax
  • Railroad retirement benefits are not taxed - Military retirement pay is exempt
  • Teacher pension income receives favorable treatment
  • Traditional IRA distributions may qualify for exemptions

These exemptions make the state more tax-friendly for retirees and military personnel.

How Do I Track My Refund?

To track your Connecticut refund, you may visit www.ct.gov/drs/site/default.asp. On the left side of the menu, mouse over "How Do I" and click the option to check the status of a refund.

Frequently Asked Questions

Do I need to file a Connecticut tax return if I only worked there part of the year?
Yes, if you earned income in Connecticut and meet the minimum income thresholds, you'll need to file a CT-1040NR/PY (nonresident/part-year resident) return.

Does Connecticut tax my out-of-state income?
Residents must report all income, including out-of-state earnings, on their state return. However, you may receive credit for taxes paid to other states to avoid double taxation.

How long does it take to receive my tax refund?
E-filed returns typically receive refunds within 2-3 weeks, while paper returns may take 6-8 weeks to process.

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.

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