How Much Is Connecticut State Income Tax?

The state of Connecticut levies an income tax on its residents and those earning income from sources within the state. This tax contributes to various public services and programs. Unlike some states that employ a flat tax rate, Connecticut utilizes a progressive income tax system. This means different portions of an individual’s income are taxed at varying rates, with higher income levels subject to higher marginal tax rates.

Income Subject to Connecticut Taxation

Connecticut’s income tax applies to various types of income received by individuals. Wages, salaries, and tips are subject to this taxation. Interest income earned from savings accounts, bonds, and other investments, along with dividend income from stocks, is included when calculating Connecticut taxable income.

Business income derived from sole proprietorships, partnerships, or S corporations also falls under the state’s tax purview. This includes profits generated from self-employment activities or distributions from pass-through entities. Rental income received from real estate properties located both inside and outside Connecticut is taxable for residents.

Capital gains realized from the sale of assets like stocks, real estate, or other investments are taxed at the same rates as other personal income in Connecticut. Pension and annuity income, including distributions from retirement plans, are subject to state income tax. A 50% deduction may apply for income from the Teachers’ Retirement System. Unemployment compensation received by individuals is also considered taxable income.

Connecticut Income Tax Rates and Brackets

Connecticut employs a progressive income tax structure with seven distinct tax brackets. For the 2024 tax year, filed in 2025, tax rates range from 2% to 6.99%.

The lowest tax rate of 2% applies to the first $10,000 for single filers and $20,000 for married individuals filing jointly. The next portion of income, up to $50,000 for single filers or $100,000 for joint filers, is taxed at 4.5%. Subsequent income tiers are subject to rates of 5%, 5.5%, 6%, 6.5%, and 6.99% for the highest income levels.

Only the income falling within a specific bracket is taxed at that bracket’s rate. For example, a single filer with $55,000 in taxable income for 2024 would pay 2% on the first $10,000, 4.5% on income between $10,001 and $50,000, and 5.5% on the remaining $5,000.

Available Deductions, Exemptions, and Credits

Connecticut taxpayers can utilize various provisions to reduce their taxable income or directly lower their tax liability. A standard deduction is available, set at $15,000 for single filers and $24,000 for married individuals filing jointly for the 2024 tax year. These amounts help lower the portion of income subject to taxation, with phase-outs applying as adjusted gross income rises. For example, the standard deduction begins to phase out for single filers with Connecticut AGI over $44,000.

Beyond the standard deduction, specific income exclusions and deductions are available. Pension and annuity income may be fully deductible for taxpayers whose federal AGI is below certain thresholds, such as $75,000 for single filers or $100,000 for joint filers. For those with higher incomes, up to 25% of Social Security benefits might be taxed, but full exemption applies below these AGI limits. Contributions to Connecticut Higher Education Trust (CHET) programs can also be deductible.

Several tax credits are offered to directly reduce the amount of tax owed. The property tax credit allows a reduction in state income tax for property taxes paid on a primary residence or motor vehicle. For the 2024 tax year, this credit can be up to $300. Eligibility for this credit has been expanded to all adult Connecticut residents, regardless of age or dependents, subject to income limitations.

The Connecticut Earned Income Tax Credit (EITC) provides a refundable credit for low to moderate-income working individuals and families. To qualify for the state EITC, taxpayers must be eligible for the federal EITC. The Connecticut EITC is set at 40% of the federal credit amount.

Filing and Payment Procedures

Individuals meeting specific criteria are required to file a Connecticut income tax return. This includes those who had Connecticut income tax withheld from their wages or made estimated tax payments. A filing requirement also applies if an individual’s gross income exceeds certain thresholds, such as $15,000 for single filers or $24,000 for married individuals filing jointly for the 2024 tax year. Taxpayers claiming the Connecticut Earned Income Tax Credit or those with a federal alternative minimum tax liability must also file a state return.

The primary form for resident individuals is Form CT-1040, Connecticut Resident Income Tax Return. Non-residents and part-year residents use Form CT-1040NR/PY. Electronic filing is available through the Connecticut Department of Revenue Services (DRS) Taxpayer Service Center, approved tax software, or a tax professional. Paper filing by mail remains an option.

Payment of any tax due can be made electronically via direct debit from a bank account through the DRS Taxpayer Service Center or by credit/debit card, though a convenience fee may apply. For those paying by mail, a check or money order made payable to the Commissioner of Revenue Services should accompany the return. Estimated tax payments are required if a taxpayer expects to owe more than $1,000 after credits and withholding; these can also be paid electronically or by mail using payment vouchers.

The standard deadline for filing Connecticut individual income tax returns and paying any tax due for the 2024 tax year is April 15, 2025. Taxpayers needing more time can request a six-month extension to file by filing Form CT-1040 EXT. This extends the time to file until October 15 but does not extend the time to pay any taxes owed. Interest and penalties may apply to any unpaid tax balance after the original April 15 due date, even if an extension to file has been granted.

Understanding Connecticut Residency for Tax Purposes

An individual’s residency status influences their Connecticut income tax obligations. Connecticut defines a full-year resident as someone whose permanent legal residence, or domicile, was in the state for the entire tax year. Alternatively, an individual can be considered a full-year resident if they maintained a permanent place of abode in Connecticut for the entire year and spent more than 183 days in the state during that tax year. Residents are taxed on all their income, regardless of where it was earned.

Non-residents, who do not meet the criteria for full-year residency, are taxed only on income derived from Connecticut sources. This includes wages earned for work performed within Connecticut, income from a business or profession carried on in the state, or rental income from real property located in Connecticut. For example, an individual living in a neighboring state but commuting to Connecticut for work would only pay Connecticut income tax on income earned from work performed in Connecticut.

Part-year residents are individuals who changed their permanent legal residence by moving into or out of Connecticut during the tax year. For these individuals, Connecticut taxes only the income earned while they were a resident of the state, in addition to any Connecticut-sourced income earned during their non-resident period.

To prevent double taxation, Connecticut offers a credit for income taxes paid to other jurisdictions. Connecticut residents and part-year residents can claim this credit against their Connecticut income tax liability for income taxes paid to another state, a local government within another state, or the District of Columbia. The credit allowed is the lesser of the tax paid to the other state or the tax Connecticut imposes on that same out-of-state income.