What to know about filing Connecticut state tax

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In a Nutshell

Due to the COVID-19 pandemic, Connecticut has extended its filing and payment deadline for 2019 income taxes to July 15, 2020. 
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This article was fact-checked by our editors and Rachel Weatherly, tax product specialist with Credit Karma. It has been updated for the 2019 tax year.

Connecticut is one of the smallest U.S. states, but it can lay claim to giving the world the giant Subway restaurant chain and the Colt revolver.

If you live in the Constitution State, you may have to file a state income tax return. But in addition to providing taxpayers with special credits, the state offers progressive income tax rates and the option to pay taxes over time.

The basics of Connecticut state tax

Whether you file on your own or have someone else prepare your state tax return, it’s important to know about deadlines, credits, tax rates and more.

If you are a resident of Connecticut for all or part of the tax year, you may be required to file a state income tax return depending on how much income you earn and if certain conditions apply to you. Part-year residents may also be required to file if they meet certain conditions.

Taxing body

The Connecticut Department of Revenue Services administers the state’s taxes, including sales tax, use tax, capital gains tax and personal income tax. If you have any questions related to your state income tax, check the agency’s list of frequently asked questions. Alternatively, you can send an email through the Contact DRS page or call 1-860-297-5962.

Filing and payment deadline

For 2019 state taxes, the state has extended the filing and payment deadline. Connecticut residents now have until July 15, 2020, to file their state returns and pay any state tax they owe for the year.

Although this year is a bit different, typically April 15 is the due date for filing and paying your state taxes each year. But it will be extended to the following business day if the 15th falls on a weekend or holiday.

If you don’t have enough information to file your Connecticut state tax return by the due date, you can request a six-month extension. That doesn’t extend your payment due date, however, so be sure to estimate how much you’ll owe and pay that amount by the original filing deadline.

Filing statuses

The state of Connecticut recognizes the same filing statuses as the federal government: single, head of household, married filing jointly, married filing separately and qualifying widow(er) with dependent child.

How your tax-filing status affects your tax bill

Connecticut state income tax rates

Connecticut has a progressive tax rate with seven income tax brackets. Here are the tax rates and corresponding tax bracket thresholds for 2019:

Tax rate

Single or married filing separately

Head of household

Married filing jointly or qualifying widow(er)


$10,000 or less

$16,000 or less

$20,000 or less




















$500,001–$1 million


$501,000 or more

$800,001 or more

More than $1 million

Connecticut state tax credits and subtractions

Connecticut allows residents to take personal exemptions, and the amount is based on their income and filing status. For 2019, the maximum exemption amount is $24,000. The exemptions phase out as income levels rise.


Subtractions work much like deductions — they reduce income and, therefore, can help lower your tax burden. Connecticut offers a few for 2019, including:

  • Organ donation expenses: If you made a living organ donation (such as bone marrow or a kidney), you may be able to subtract up to $10,000 in related expenses, including lost wages, travel and housing, and medical costs.
  • Income tax exemption for teacher pensions – Qualifying taxpayers are allowed to reduce their Connecticut adjusted gross income by 25% of the income they receive from the state teacher’s retirement system.


The state offered five tax credits in 2017 to help taxpayers reduce how much tax they owe or to increase their refund. These credits could be available for 2018 as well.

  • Personal tax credit: This credit is available for low- to moderate-income taxpayers and can be between 1% and 75% of your tax bill. The credit, which differs according to your filing status, phases out as your adjusted gross income, or AGI, increases — and is eliminated altogether if your AGI exceeds $64,500 for single filers, $100,500 for those married filing jointly or qualified widow(er)s, $52,500 for those married filing separately and $78,500 for head of household filers.
  • Property tax credit: If you’re 65 or older and have at least one dependent that you claimed on your federal tax return, you may get a credit of up to $200 for property tax paid on a primary residence or motor vehicle during the year, based on your filing status and income.
  • Earned income tax credit: If you qualify for and claim the federal earned income tax credit on your federal refund, you may qualify for an extra credit on your state tax return that’s worth 23% of the federal credit you claim for the same tax year.
  • Angel investor tax credit: If you invest at least $25,000 in an eligible business during the tax year, you may be able to claim a credit of 25% of your investment, up to $500,000.


What's the difference between a tax deduction vs. a tax credit?

A tax deduction reduces the amount of income you pay income tax on, and it could mean you pay less in taxes. A tax credit is a dollar-for-dollar reduction in the amount of tax you owe.

Learn more about how tax deductions and tax credits work.

How to file your Connecticut state tax

You can e-file your state tax return for free through the Taxpayer Service Center, or via paid or free tax software programs.

If you’d prefer to file a paper return, you can download and print your tax forms — including Form CT-1040 — from the DRS website and fill them out with a pen. Mail your CT-1040 return to:

If you expect a refund:

Department of Revenue Services

P.O. Box 2976

Hartford, CT 06104-2976

If you include a payment with your return:

Department of Revenue Services

P.O. Box 2977

Hartford, CT 06104-2977

To get free state tax preparation help from the DRS, call 1-860-297-5962 from 8:30 a.m. to 4:30 p.m. Eastern time Monday through Friday, or go in person to one of its field offices after checking what documents you need to bring. This assistance is only for Connecticut taxes, not for federal tax returns

If you still have lingering concerns, the department offers help through its Problem Resolution/Taxpayer Advocate office.

If you owe and can’t pay

If you can’t pay your tax bill by the due date, you may be able to request an installment agreement payment plan to pay it off over time. To qualify, you must:

  • Not already have an account in collections with the DRS, or have an account under warrant, bankruptcy, suspense or criminal investigation
  • Have filed all your returns
  • Owe $10,000 or less
  • Be able to pay off the full amount within 12 months

Keep in mind, though, that you may have to pay interest and late-payment penalties until the balance is paid in full.

Tracking your Connecticut tax refund

If you’re expecting a refund, you can check the status by calling 1-860-297-5962. Or, check your refund status online by visiting the Taxpayer Service Center page and clicking on “Check on the Status of Your Refund” on the left-hand side of the page.

You’ll need to provide your Social Security number or your spouse’s Social Security number if you filed jointly and their information is first on the return, along with the amount of the refund you’re expecting.

To get your refund faster, the DRS recommends you file your state tax return electronically and choose direct deposit instead of getting a paper check.

Bottom line

It’s not enough just to know when to file your Connecticut state tax return to avoid penalties. Take the time to determine whether you qualify for one or more of the state’s tax credits or subtractions, which can help reduce your tax bill.

The more you know about your state’s tax return process, the easier it will be to file at tax time.

Rachel Weatherly is a tax product specialist with Credit Karma. She studied accounting and finance at Western Carolina University and has also worked as a tax analyst. You can find her on LinkedIn.

About the author: Ben Luthi is a personal finance freelance writer and credit cards expert. He holds a bachelor’s degree in business management and finance from Brigham Young University. In addition to Credit Karma, you can find his wo… Read more.