Connecticut State Taxes: Rates, Brackets, and How to File
Connecticut collects several types of state taxes, including a personal income tax, a 6.35% sales tax, and local property taxes. For most residents, the primary obligation is the personal income tax, administered by the Department of Revenue Services (DRS).
Connecticut uses a graduated income tax system with seven brackets ranging from 2% to 6.99% for the 2025 tax year. Residents, nonresidents and part-year residents who earn income within the state must file an annual income tax return. Residents file using Form CT-1040; nonresidents and part-year residents use Form CT-1040NR/PY.
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.
You may also be required to file below these thresholds if you had Connecticut income tax withheld, made estimated tax payments, had a federal alternative minimum tax liability or are claiming the Connecticut Earned Income Tax Credit (CT EITC).
Connecticut Income Tax Rates and Brackets
Connecticut's income tax system is graduated so only the portion of income within each bracket is taxed at that rate, not your total income. For the 2025 tax year, Connecticut has seven income tax brackets with rates ranging from 2% to 6.99%, varying by taxable income and filing status.
In addition to the personal income tax, Connecticut imposes a 7.5% corporate income tax rate on businesses and a 6.35% state sales and use tax. Unlike many states, Connecticut does not add local sales taxes on top of the state rate, keeping the sales tax structure straightforward for residents and businesses.
Connecticut Tax Deductions and Exemptions
Connecticut provides several exemptions that can meaningfully reduce your state tax liability, particularly for retirees and military personnel.
- Social Security Benefits: If your federal AGI is $75,000 or less (single or married filing separately) or $100,000 or less (married filing jointly or head of household), your benefits are fully exempt from Connecticut income tax.
- Retirement, Military and Pension Income: Railroad retirement benefits (Tier I and Tier II) and military retirement pay are fully exempt from Connecticut income tax. Teacher pension income also receives favorable treatment depending on the pension type and amount.
- IRA Distributions: Starting in 2025, Connecticut allows a deduction for 75% of IRA distributions from state taxable income, up from 50% in prior years. This deduction is scheduled to increase to 100% by 2026.
Filing Deadline and Extensions
The Connecticut state income tax deadline is April 15, aligned with the federal deadline. Any tax owed after this date is subject to a 10% penalty, with a minimum penalty of $50, plus 1% interest per month on the unpaid balance until paid in full.
If you expect a refund or owe no additional tax, Connecticut automatically grants a six-month filing extension when you file a federal extension; no separate state form is required. The extended filing deadline is October 15.
Remember that requesting an extension (Form CT 1040EXT) applies to filing only; it does not extend the payment deadline.
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 (Form CT-1040ES), they can be filed and paid electronically using myconneCT at portal.ct.gov/DRS-myconneCT, or by mail to the DRS. When paying by mail, send vouchers and payments to:
Department of Revenue Services
PO Box 2932
Hartford CT 06104-2932
If an error is discovered and an amendment is needed (Form CT-1040X), taxpayers may file and pay electronically using myconneCT or mail it to:
Department of Revenue Services
PO Box 2978
Hartford, CT 06104-2935
For questions on amended returns or their status, you may call the DRS at 860-297-5962 or email DRS@ct.gov.
How To Track Your Connecticut Tax Refund
To check the status of your Connecticut tax refund, visit the "Where's my Refund?" tool on the DRS website. You'll need your Social Security number and the refund amount from your return. E-filed returns with direct deposit are processed much faster than paper returns, which typically take within 10-12 weeks.
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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 do I track my Connecticut tax refund?
To check the status of your Connecticut tax refund, visit the "Where's My Refund?" tool on the DRS website. You'll need your Social Security number and the refund amount from your return. E-filed returns with direct deposit are processed faster; paper returns typically take 10-12 weeks.
What is the CT state tax filing deadline?
April 15, aligned with the federal deadline. An automatic six-month extension to October 15 is available, but any taxes owed must still be paid by April 15 to avoid penalties.
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.