Connecticut has a state income tax, and it applies to most residents and workers

Yes, Connecticut charges state income tax on wages, investment income, and other earnings. The tax rate varies based on your income level — it ranges from 3% on the lowest brackets to 6.99% on the highest. Connecticut residents pay this tax on income earned anywhere, and nonresidents pay it only on income earned within the state.

The state also taxes capital gains, dividends, and interest income. If you work in Connecticut but live in another state, you may owe Connecticut tax on your wages, though some states have reciprocal agreements that can reduce or eliminate this. Your employer typically withholds Connecticut income tax from your paycheck automatically, similar to federal withholding.

Key Takeaways

  • Connecticut income tax rates range from 3% to 6.99% depending on your income bracket, with rates increasing as income rises.
  • The state taxes wages, capital gains, dividends, and interest income for residents and nonresidents who earn money in Connecticut.
  • Your employer should withhold Connecticut income tax from your paycheck, but you can adjust your withholding by filing a CT-W4 form with your employer.
  • Connecticut residents who work out of state may still owe Connecticut tax depending on where they live and work, though some reciprocal agreements exist.
  • You file Connecticut income tax using Form CT-1040 or CT-1040NR, due by April 15 unless you receive an extension.

Connecticut income tax brackets and rates for 2024

Connecticut uses a progressive tax system, meaning your tax rate increases as your income increases. The state has five tax brackets. For the 2024 tax year, single filers face rates of 3%, 5%, 5.5%, 6%, and 6.99% depending on which bracket their income falls into. Married couples filing jointly have higher income thresholds before moving into each bracket.

The exact dollar amounts for each bracket change yearly. For example, in 2024, a single filer enters the 5% bracket at $21,000 of taxable income and the highest 6.99% bracket at $500,000. Married filers have different thresholds — the top bracket begins at $750,000 for joint returns. You can find the current year's brackets on the Connecticut Department of Revenue Services website.

Connecticut also allows a standard deduction that reduces your taxable income before you calculate tax owed. The standard deduction amount varies by filing status and age. Older residents (65 and over) receive a higher standard deduction than younger filers.

What income Connecticut taxes and what it does not

Connecticut taxes most forms of income: W-2 wages from employment, self-employment income, capital gains from selling stocks or property, dividend income, and interest earned on savings accounts and bonds. If you receive rental income from property you own, that is also taxable. Retirement distributions from IRAs and 401(k)s are taxed as ordinary income in the year you withdraw them.

Connecticut does not tax Social Security benefits, regardless of your total income. Military pensions are also exempt from Connecticut income tax. Some retirement income receives preferential treatment — if you are 60 or older, you may exclude a portion of your pension or retirement account distributions, up to a set limit per year. This exclusion does not apply to Social Security.

Certain types of income are not taxed at all: gifts, inheritances, life insurance proceeds, and workers' compensation benefits. Scholarships used for tuition and required course materials are also exempt, though room and board portions are taxable.

How withholding works and how to adjust it

When you start a job in Connecticut, your employer asks you to complete a CT-W4 form (Connecticut Withholding Certificate). This form tells your employer how much Connecticut income tax to deduct from each paycheck. Your employer sends that withheld amount to the state on your behalf. Most people have the correct amount withheld and receive a refund or owe a small amount when they file their annual return.

If you find that too much or too little is being withheld, you can file a new CT-W4 with your employer at any time. Common reasons to adjust withholding include a major life change (marriage, divorce, new child), a second job, or significant investment income. You can claim additional allowances to reduce withholding or claim zero allowances to increase it.

If you are self-employed or have income that is not subject to withholding, Connecticut requires you to make quarterly estimated tax payments. These are due on April 15, June 15, September 15, and January 15 of the following year. Underpayment can result in penalties and interest.

Filing your Connecticut income tax return

Connecticut residents file using Form CT-1040 (Connecticut Individual Income Tax Return). Nonresidents who earned income in Connecticut file Form CT-1040NR. Both forms are due by April 15 unless you receive an extension. If you file a federal extension (Form 4868), that extension also applies to your Connecticut return.

You can file your Connecticut return on paper by mailing it to the Connecticut Department of Revenue Services, or you can file electronically through the state's online system or through tax software. Many tax software programs include Connecticut forms and can file both federal and state returns together. If you use a tax preparer, they can file electronically on your behalf.

When you file, you report all income earned during the year, claim deductions and credits you are may have access to to, and calculate your total tax owed. The state compares this to the amount already withheld from your paychecks. If you withheld more than you owe, you receive a refund. If you withheld less, you owe the difference.

Nonresidents and people who work across state lines

If you live in another state but work in Connecticut, you owe Connecticut income tax on your Connecticut wages. You also file a return in your home state, but most states allow you to claim a credit for taxes paid to Connecticut to avoid double taxation. The amount of credit varies by state.

Connecticut has reciprocal tax agreements with certain neighboring states. If you live in New Jersey, New York, or Pennsylvania and work in Connecticut, you may not owe Connecticut tax on your wages, depending on the specific agreement and your circumstances. You would instead pay tax only to your home state. Check with the Connecticut Department of Revenue Services or your state's tax authority to confirm whether a reciprocal agreement applies to you.

Nonresidents who have Connecticut-source income (such as rental property in the state or a business operated there) must file Form CT-1040NR and pay tax on that income. The form asks you to identify which income is Connecticut-source and which is from other states.

Credits and deductions that reduce your Connecticut tax

Connecticut offers several tax credits that directly reduce the amount of tax you owe. The Earned Income Tax Credit (EITC) is available to lower-income workers and is based on your federal EITC. Connecticut's version is a percentage of your federal credit. You claim it on your state return using the same income and family information you used for your federal return.

Other credits include the Child and Dependent Care Credit, the Education Credit (for tuition paid to Connecticut colleges), and the Property Tax Credit for renters and homeowners with lower incomes. Some credits are refundable, meaning if the credit exceeds your tax owed, you receive the difference as a refund. Others are nonrefundable and can only reduce your tax to zero.

Deductions reduce your taxable income before you calculate tax. The standard deduction is the most common. If you itemize instead, you can deduct mortgage interest, property taxes, charitable donations, and certain other expenses. Connecticut allows you to deduct the full amount of property taxes you paid, with no cap, which is more generous than the federal limit.

Frequently Asked Questions

Do I have to file a Connecticut return if I only lived there part of the year?

Yes, if you were a Connecticut resident for any part of the tax year and had Connecticut-source income, you must file. You report income for the entire year, not just the months you lived there. However, you may be able to claim a credit for taxes paid to another state if you moved and paid tax there for part of the year.

What happens if I do not file or pay Connecticut income tax?

The Connecticut Department of Revenue Services can assess penalties and interest on unpaid taxes. Penalties typically start at 5% of the unpaid amount and can increase. Interest accrues daily. If you owe a significant amount, the state can place a lien on your property or garnish your wages. Filing late is better than not filing at all — the penalty for filing late is smaller than the penalty for not filing.

Can I get an extension to file my Connecticut return?

Yes. If you file a federal extension using Form 4868, that automatically extends your Connecticut deadline to October 15. You do not need to file a separate state extension. However, an extension to file is not an extension to pay — you should estimate your tax owed and pay it by April 15 to avoid interest charges on any unpaid balance.

Are retirement distributions from my 401(k) or IRA taxed by Connecticut?

Yes, distributions are taxed as ordinary income in Connecticut. However, if you are 60 or older, Connecticut allows you to exclude up to $6,000 per year of retirement income (including pensions, IRA distributions, and 401(k) withdrawals). This exclusion does not apply to Social Security. The exact limit changes yearly, so check the current year's limit on the Department of Revenue Services website.

Do I owe Connecticut tax if I work remotely for a company outside Connecticut?

If you are a Connecticut resident, you owe Connecticut tax on all income, regardless of where your employer is located or where you work. If you are a nonresident who works remotely for an out-of-state company but happen to live in Connecticut temporarily, you generally do not owe Connecticut tax on that income. Your residency status determines your tax obligation.