Connecticut collects state income tax on wages, investment income, and retirement distributions

Connecticut has a state income tax. The tax applies to wages you earn from a job, interest and dividends from investments, income from self-employment, and distributions from retirement accounts. The tax rate varies depending on your income level — Connecticut uses a graduated tax system where higher earners pay a higher percentage.

The state income tax is separate from federal income tax. You will owe both Connecticut state tax and federal tax on most income. Connecticut residents file a state tax return in addition to their federal return, usually at the same time.

Key Takeaways

  • Connecticut residents pay state income tax on wages, investment income, retirement withdrawals, and self-employment income.
  • Tax rates range from 3% to 6.99% depending on your income bracket, with higher earners paying a higher percentage.
  • You file a Connecticut state return separate from your federal return, typically using the same income figures.
  • Some types of income, including Social Security benefits and certain retirement account distributions, may be partially or fully exempt from Connecticut state tax.

Connecticut income tax rates and brackets

Connecticut's income tax uses tax brackets that change each year. For 2024, the rates start at 3% for the lowest income earners and increase to 6.99% for the highest earners. The exact income ranges for each bracket are adjusted annually for inflation, so the dollar amounts that trigger each rate change from year to year.

Your tax bracket depends on your filing status — single, married filing jointly, married filing separately, or head of household. A married couple filing jointly reaches higher income thresholds before moving into a higher tax bracket than a single filer with the same total income. You can find the current year's brackets on the Connecticut Department of Revenue Services website.

Who must file a Connecticut state return

You must file a Connecticut state return if you lived in Connecticut for any part of the tax year and your income exceeds the filing threshold for your situation. The threshold depends on your age, filing status, and type of income. Generally, if you earned enough income that you are required to file a federal return, you also need to file a Connecticut return.

Even if your income is below the filing threshold, you may want to file anyway — for example, if you had taxes withheld from your paychecks, filing allows you to claim a refund. Connecticut also offers a property tax credit and an earned income tax credit that require you to file to receive them.

Income that is exempt or partially exempt from Connecticut tax

Social Security benefits are not taxed by Connecticut, even though they may be taxed at the federal level. Distributions from certain retirement accounts also receive special treatment. Withdrawals from a traditional IRA or 401(k) are taxable, but Connecticut allows a deduction for some retirement income depending on your age and total income.

If you are age 60 or older, you may deduct up to $6,000 of retirement income from pensions, annuities, IRAs, and 401(k)s. The deduction phases out as your total income rises. Military pensions are fully deductible regardless of age. Interest from U.S. Treasury bonds and certain other federal obligations is exempt from Connecticut tax, though it is still subject to federal tax.

How Connecticut collects income tax from your paycheck

If you work for an employer in Connecticut, your employer withholds state income tax from your paycheck, just as they withhold federal income tax. You provide a W-4 form to your employer, which tells them how much to withhold. The amount withheld is based on your income, filing status, and the number of dependents you claim.

If you do not have enough withheld during the year, you may owe tax when you file your return. If too much is withheld, you receive a refund. Self-employed people do not have an employer to withhold tax, so they must make quarterly estimated tax payments to Connecticut throughout the year or pay the full amount when they file their annual return.

Filing your Connecticut state return

Connecticut residents file using Form CT-1040, the Connecticut Individual Income Tax Return. You can file on paper by mailing the form to the Connecticut Department of Revenue Services, or you can file electronically through the state's online system or through tax software. Most tax preparation software includes Connecticut forms and can file electronically on your behalf.

The important date to file is the same as the federal important date — typically April 15 of the following year. If you need more time, you can request an extension, which gives you until October 15 to file. An extension to file does not extend the important date to pay any tax you owe; you should pay by April 15 to avoid penalties and interest.

What happens if you move out of Connecticut

If you move out of Connecticut during the year, you are a part-year resident and file a Connecticut return only for the months you lived in the state. You report only the income you earned while living in Connecticut. If you moved to another state, you may also owe tax to that state on income earned there.

If you moved out of Connecticut and no longer live there, you do not file a Connecticut return unless you have Connecticut-source income — for example, rental income from property you own in the state or income from a business operated in Connecticut. Some states have reciprocal agreements with Connecticut that affect how your income is taxed, so check with your new state's tax authority if you moved across state lines.

Frequently Asked Questions

Does Connecticut tax Social Security?

No. Connecticut does not tax Social Security benefits at the state level. However, your Social Security income may still be subject to federal income tax depending on your total income and filing status.

What is the Connecticut state income tax rate?

Connecticut uses a graduated tax system with rates ranging from 3% to 6.99% depending on your income bracket. The exact brackets change each year. You can find the current year's rates on the Connecticut Department of Revenue Services website.

Can I deduct my federal income tax from my Connecticut state tax?

No. Connecticut does not allow you to deduct federal income tax paid. You calculate your Connecticut tax based on your income after taking the standard deduction or itemizing deductions, but federal tax payments are not deductible.

Do I have to file a Connecticut return if I work remotely for an out-of-state company?

If you live in Connecticut and work remotely, you typically owe Connecticut state tax on your wages even though your employer is located elsewhere. Connecticut taxes income earned by residents regardless of where the employer is based. Check with the Connecticut Department of Revenue Services if your situation is unusual.

What if I did not file a Connecticut return in previous years?

Contact the Connecticut Department of Revenue Services. You may be able to file back returns, and the department can tell you whether you owe tax for those years. Filing voluntarily is generally better than waiting for the state to contact you.