Connecticut State Income Tax in 2025: A Guide

Connecticut introduced its first state income tax—a flat rate of 4.5%—on August 22, 1991, to help offset a $963 million budget deficit. Today, the state uses a progressive state income tax system with seven tax rates—ranging from 2% to 6.99%—for the 2024 tax year (the taxes you’ll file in 2025).  

The state taxes you owe depend on how much money you make, your filing status, and any deductions or credits you might have. Connecticut’s tiered tax system means that the state income tax rate rises as your taxable income increases. 

Whether you’re a full-year resident, part-year resident, or nonresident earning income in Connecticut, understanding the state’s tax brackets and rules is important to filing accurately and keeping your tax bill as low as possible.  

Let’s explore what you need to know for the 2024 tax year in Connecticut. 

*Note that you are still responsible for federal taxes if you meet the IRS income filing threshold. This article addresses state-specific taxes only.

Connecticut state income tax rates

Connecticut has seven tax brackets, starting at 2% and climbing to 6.99%. Unlike states with a flat tax rate, Connecticut’s system is set up so those earning more contribute a higher percentage. Connecticut state taxes for the 2024 tax year are due by April 15, 2025, aligning with the federal tax deadline. 

Curious about how these tax brackets apply to your filing status? Here’s a breakdown of the income tax brackets and rates for single filers, married couples, and other filing statuses.  

Tax Rate	Taxable Income
	Single and Married Filing Separately	Heads of Household	Married Filing Jointly
2%	$0 to $10,000	$0 to $16,000	$0 to $20,000
4.5%	$10,001 to $50,000	$16,001 to $80,000	$20,001 to $100,000
5.5%	$50,001 to $100,000	$80,001 to $160,000	$100,001 to $200,000
6%	$100,001 to $200,000	$160,001 to $320,000	$200,001 to $400,000
6.5%	$200,001 to $250,000	$320,001 to $400,000	$400,001 to $500,000
6.9%	$250,001 to $500,000	$400,001 to $800,000	$500,001 to $1 million
6.99%	More than $500,000	More than $800,000	More than $1 million

Source: Connecticut Office of Legislative Research

Who has to file Connecticut state income tax?

You’ll need to file a Connecticut state income tax return if you’re a full-time resident, part-time resident, or nonresident who makes money from Connecticut sources. Here are the gross income thresholds—the minimum amount you need to earn for the state to require you to file taxes—for different filing statuses: 

Status	Filing Threshold
Single	$15,000
Married filing jointly or qualifying surviving spouse	$24,000
Married filing separately	$12,000
Head of household	$19,000

You’ll also need to file if you’ve: 

• Had state tax withheld 
• Made estimated payments 
• Received a pass-through entity (PE) tax credit (allows business owners of pass-through entities to offset taxes paid at the entity level against their personal income tax liability).  

Other reasons to file include having a federal alternative minimum tax liability or claiming the Connecticut Earned Income Tax Credit (EITC), which gives low- to moderate-income workers a state credit based on their federal EITC. 

How Connecticut residency impacts tax filing

Connecticut defines residency for tax purposes based on where you live and earn income. There are three residency statuses: resident, part-year resident, and nonresident. Each determines how the state taxes your income. Whether you live in Connecticut full time or earn income there for part of the year, understanding your status is important for filing taxes correctly. 

The table below explains each residency status, who qualifies, and how Connecticut taxes income for each group.

Residency Status	Definition	How Connecticut Taxes Income
Resident	You lived in Connecticut for the entire tax year or maintained a permanent place of abode and spent more than 183 days in the state.	Connecticut taxes all your income, regardless of where you earned it.
Part-year resident	You lived in Connecticut for part of the year, either moving in or out of the state.	Connecticut taxes income earned while a resident, as well as any Connecticut-sourced income.
Nonresident	You lived outside Connecticut during the year but must file a Connecticut tax return.	Connecticut taxes only Connecticut-sourced income.

Source: Connecticut State Department of Revenue Services

Other income tax considerations in Connecticut

Connecticut offers specific rules and deductions for different types of income and assets. Here’s how these might apply to you: 

Retirement and pension income 

• If you receive income from the Teachers’ Retirement System (TRS), you can deduct 50% of it on your state taxes. 
• Earn a pension or annuity? If your federal adjusted gross income (AGI) is below $75,000 (single, married filing separately, or head of household) or $100,000 (married filing jointly), you can deduct 100% of that income. For higher incomes, the deduction phases out gradually. 
• Receiving individual retirement account (IRA) distributions (not including Roth IRAs)? Starting in 2024, you can deduct 50% of those amounts, with deductions increasing to 100% by 2026. 
• If you’re retired from the railroad (tier I and tier II railroad retirement benefits) or military, you can deduct 100% of your retirement pay. 

Investment income 

Any capital gains you earn are taxed at the same rates as your personal income. 

Social Security income 

If your federal AGI is less than $75,000 (single or married filing separately) or $100,000 (married filing jointly or head of household), you can deduct all your Social Security benefits. For higher incomes, up to 25% of your benefits may be taxed. 

Military income 

If you are a Connecticut resident, your military income is subject to state income tax. If Connecticut is your legal residence but you and your spouse are stationed elsewhere, you’ll still need to file and pay Connecticut income tax on all your earnings. Nonresidents who entered the military while residents of another state are not subject to Connecticut income taxes on military pay earned while stationed within the state. However, any other income earned by nonresidents while stationed within Connecticut are subject to Connecticut income taxes.

Common Connecticut state tax deductions and credits

Connecticut offers several tax deductions and credits to reduce your taxable income or lower your overall tax bill. Here’s a quick look at a few deductions and credits and how they work. 

Tax credit	Description	Amount
Personal Exemptions	Reduces taxable income for filers under income thresholds. Phases out as income rises.	Up to $15,000 (single), $12,000 (married filing separately), $19,000 (head of household), $24,000 (married filing jointly).  Fully phased out above Connecticut AGI of $44,000 (single), $35,000 (married filing separately), $56,000 (head of household), $71,000 (married filing jointly).
Personal Tax Credit	Reduces tax liability by 1% to 75%, phasing out at higher incomes.	1%–75% of tax due.
Income Taxes Paid to Qualifying Jurisdictions	Credit for taxes paid to other states or jurisdictions on income also taxed in Connecticut.	The lesser amount between the taxes you paid to the other jurisdiction and the Connecticut state tax you owe on that same income.
Property Tax Credit	Credit for property taxes paid on a primary residence or vehicle in Connecticut. Phases out at higher incomes.	Up to $300.
Earned Income Tax Credit (EITC)	Refundable credit equal to 40% of the federal EITC for qualifying low-income workers.	$253–$3,132 (based on dependents).
Credit for Stillbirths	Credit for the birth of a stillborn child, provided the child would have been a dependent.	$2,500.
Historic Homes Rehabilitation Tax Credit	Refundable credit for costs incurred rehabilitating a historic home.	30% of rehabilitation costs.

For a list of Connecticut’s tax credits and exemptions, review their state tax incentives. 

How to file Connecticut state income tax

Filing your Connecticut state income taxes doesn’t have to be complicated. TurboTax is here to help, whether you prefer to handle your taxes yourself or you want an expert to take care of everything for you. Regardless of how you use TurboTax, we’ll walk you through the process step by step, ensuring you claim every deduction and credit you’re eligible for. 

If you’d rather leave it to a pro, you can connect with a local tax expert in Connecticut who will prepare and file your return, ensuring nothing is missed. No matter your situation—resident, part-year resident, or nonresident—TurboTax makes filing smooth, accurate, and stress-free, helping you get your biggest possible refund.