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

Yes, Connecticut has a state income tax. The tax applies to wages you earn from a job, interest and dividends from investments, capital gains, and distributions from retirement accounts. Connecticut's income tax rate varies depending on your filing status and total income—it is not a flat rate across all earners.

The state uses a progressive tax system, meaning higher earners pay a higher percentage of their income in taxes. Tax brackets change each year, and Connecticut adjusts them for inflation. If you work in Connecticut or live there, you will owe state income tax on most types of income, even if you also pay federal income tax.

Key Takeaways

  • Connecticut taxes wages, investment income, retirement distributions, and capital gains at rates that range from roughly 3% to 6.99% depending on your income level.
  • The state uses tax brackets that adjust yearly for inflation, so your rate depends on your total income and filing status.
  • If you work in Connecticut but live in another state, you may owe Connecticut tax on wages earned there, though you can claim a credit on your home state return to avoid double taxation.
  • Certain types of income, including Social Security benefits and some pension income, receive partial or full exemptions from Connecticut state tax.
  • You file Connecticut taxes using Form CT-1040 (the resident return) or Form CT-1040NR (the nonresident return) by the same April important date as federal taxes.

Connecticut income tax rates and brackets for 2024

Connecticut's income tax brackets for 2024 range from 3% on the lowest income to 6.99% on the highest. The exact dollar amounts where each bracket begins depend on whether you file as single, married filing jointly, married filing separately, or head of household. For example, a single filer in 2024 pays 3% on income up to roughly $21,000, then 5% on income between $21,000 and $52,000, and continues into higher brackets as income rises.

The state publishes updated brackets each January on the Connecticut Department of Revenue Services website. Because brackets adjust for inflation, the dollar amounts shift slightly year to year, but the percentage rates themselves remain stable. You can find the current year's brackets on the DRS website under "Tax Rate Information" or in the instructions that come with Form CT-1040.

Types of income Connecticut taxes

Connecticut taxes most forms of income. Wages from employment are taxed at your full bracket rate. Interest income from savings accounts and bonds is taxable. Dividend income from stocks is taxable. Capital gains—the profit you make when you sell an investment at a higher price than you paid—are taxed as ordinary income. Distributions from traditional IRAs, 401(k) plans, and other retirement accounts are taxable in the year you receive them.

Self-employment income is also taxable. If you run a business or freelance, you report that income on your Connecticut return and pay tax on the net profit after deducting business expenses. Rental income from property you own is taxable as well. However, Social Security benefits are not taxed by Connecticut, and certain pension income may be partially or fully exempt depending on your age and the source of the pension.

Who must file a Connecticut tax return

You must file a Connecticut return if you lived in the state for any part of the tax year and your income exceeds the filing threshold. The threshold varies by age and filing status. For 2024, a single person under 65 must file if their income is over roughly $15,000. A married couple filing jointly must file if their combined income exceeds roughly $30,000. If you are 65 or older, the threshold is higher.

Even if your income is below the threshold, you may want to file anyway if you had taxes withheld from your paychecks or if you are owed a refund. Nonresidents who worked in Connecticut during the year must also file, using Form CT-1040NR instead of the resident form. The filing important date is the same as the federal important date—usually April 15, though it shifts if that date falls on a weekend or holiday.

Tax withholding and estimated payments

If you work as an employee in Connecticut, your employer withholds state income tax from your paycheck, just as they do for federal tax. The amount withheld depends on the W-4 form you complete when you start the job. You can adjust your withholding at any time by submitting a new W-4 to your employer's payroll department.

If you are self-employed or have income that is not subject to withholding—such as rental income or investment income—you may need to make quarterly estimated tax payments to Connecticut. These are due on April 15, June 15, September 15, and January 15. If you expect to owe more than $400 in state tax for the year and do not have enough withheld, the state may assess a penalty if you do not pay estimated tax. You can calculate whether you need to pay estimated tax using the worksheet in the Form CT-1040 instructions.

Nonresidents and part-year residents

If you do not live in Connecticut but worked there during the year, you owe Connecticut tax on the wages you earned in the state. You file Form CT-1040NR (Nonresident Return) instead of the resident form. You report only the income you earned in Connecticut, not income from other states or sources outside Connecticut.

If you moved to or from Connecticut during the year, you are a part-year resident. You file Form CT-1040 and report all your income for the entire year, but you may be able to claim a credit for taxes paid to another state on income earned there. This credit prevents you from paying tax on the same income to two states. The Connecticut DRS website has worksheets to help you calculate this credit.

Deductions and credits available in Connecticut

Connecticut allows a standard deduction, which reduces the amount of income you pay tax on. For 2024, the standard deduction for a single filer is roughly $15,000, and for married filing jointly it is roughly $30,000. These amounts adjust yearly for inflation. You can claim the standard deduction or itemize deductions if itemizing results in a larger deduction, though most Connecticut filers use the standard deduction.

Connecticut also offers several tax credits that reduce the tax you owe. The Earned Income Tax Credit (EITC) is available to lower-income workers and is worth more in Connecticut than the federal credit alone. The Property Tax Credit helps homeowners and renters with property tax or rent burdens. The Child and Dependent Care Credit covers some costs of child care. You claim these credits on your Form CT-1040 or on the schedules that accompany it. The DRS website lists all available credits and the income limits for each.

Frequently Asked Questions

Do I have to pay Connecticut income tax if I work there but live in another state?

Yes, you owe Connecticut tax on wages you earn while working in the state. You file Form CT-1040NR and report only the income earned in Connecticut. You can claim a credit on your home state return for taxes paid to Connecticut, which prevents double taxation on the same income.

Is Social Security taxed in Connecticut?

No, Connecticut does not tax Social Security benefits. If Social Security is your only income, you do not need to file a Connecticut return. If you have other income above the filing threshold, you must file, but you do not report the Social Security amount as taxable income.

What happens if I do not file a Connecticut tax return when I should have?

The Connecticut DRS may assess penalties and interest on unpaid taxes. If you owe a refund, you have three years to claim it before the state keeps the money. If you missed a important date, you can still file a late return. Contact the DRS or consult a tax professional to understand your options and any penalties owed.

Can I deduct federal income tax paid from my Connecticut return?

No, Connecticut does not allow a deduction for federal income tax paid. You can only deduct state and local taxes (SALT) if you itemize deductions on your federal return, and that deduction is capped at $10,000 per year under current federal law. Connecticut's standard deduction is separate from federal deductions.

Where do I find the current Connecticut tax forms and instructions?

The Connecticut Department of Revenue Services publishes all tax forms and instructions on its website at portal.ct.gov/DRS. You can read Form CT-1040 (resident return), Form CT-1040NR (nonresident return), and all schedules and worksheets there. The site also has links to current tax rates, brackets, and credits for the year you are filing.