How to File Your Connecticut Tax Return for 2024

Filing your Connecticut state income tax return can feel overwhelming—especially with changes in forms, credits, and payment rules each tax year. Whether you're a full-year resident, part-year resident, or a Connecticut nonresident with income from Connecticut sources, this guide will walk you through how to file your Connecticut tax return for 2024. It covers everything from which tax forms to use and how to prepare supporting federal tax forms to choosing the proper filing method and making secure state tax payments.

The Connecticut Department of Revenue Services (DRS) requires most individuals with Connecticut income or withholding to file a CT state return. If you lived in the state for the entire tax year or maintained a legal residence (permanent place of abode), you are generally considered a resident for tax purposes. Even if you're not a resident, you may still need to file a return if you earned money from Connecticut sources, claimed credits, or had tax withheld. Understanding your status and obligations is essential to filing tax returns correctly and avoiding issues with refunds or penalties.

This guide is designed to help you prepare, file, and pay your Connecticut state tax efficiently. Whether you’re married filing jointly, single, or managing a household, you’ll find instructions on calculating income taxes, claiming credits, reporting out-of-state income, and submitting payments to the DRS. We’ll also cover where to mail paper forms, how to use myconneCT, and how to track your refund. If you’ve ever asked how to file your Connecticut tax return for 2024, this step-by-step resource has you covered

Overview of Connecticut State Income Tax for 2024

Who Needs to File

Connecticut residents and certain nonresidents must file a state income tax return if they meet specific conditions for the 2024 tax year.

• Connecticut residents with income or tax activity: If you were a full-year resident of Connecticut and had Connecticut income tax withheld, made estimated tax payments, claimed credits like the Pass-Through Entity Tax Credit, or had a federal alternative minimum tax liability, you must file.
  
  
• Nonresidents and part-year residents with Connecticut-sourced income: If you earned income from Connecticut sources but were not a full-year resident, you may still be required to file Form CT-1040NR/PY.
  
  
• Taxpayers claiming Connecticut credits or paying AMT: You must also file if you claim the Connecticut Earned Income Tax Credit or had federal AMT liability.
  
  

Income Thresholds for 2024

Based on your filing status, your gross income determines whether you must file a Connecticut return.

• Single or head of household filers: You must file if your gross income exceeds $15,000 as a single filer or $19,000 as a head of household.
  
  
• Married filing jointly or separately: Married couples filing jointly must file if their income exceeds $24,000. Those filing separately must file if they earn more than $12,000.
  
  
• Low-income earners with specific tax activity: Even if your income is below these thresholds, you may still need to file if you had Connecticut tax withheld or want to claim credits.
  
  

Key Filing Deadlines

The standard due date for Connecticut income tax returns follows the federal deadline.

• Regular deadline for most taxpayers: The 2024 Connecticut state tax return is due on or before Monday, April 15, 2025.
  
  
• Fiscal-year filers or businesses with non-calendar tax years: If your tax year doesn’t end in December, your return is due by the 15th day of the fourth month after your fiscal year ends.
  
  

What’s New for 2024

Connecticut has implemented several tax law changes that may affect your 2024 state income tax return. These updates include reduced income tax rates, new credits, and changes to pension withholding.

Reduced Income Tax Rates

• Lowered tax rates for low- and middle-income brackets: For 2024, the 3% income tax rate on the first $10,000 for single filers and the first $20,000 for joint filers is reduced to 2%. The 5% bracket for the next $40,000 (single) and $80,000 (joint) is reduced to 4.5%.
  
  
• Rate reductions are capped based on income: These reduced rates apply only if your Connecticut adjusted gross income is $150,000 (single filers) or $300,000 or less (married filing jointly). Taxpayers above these thresholds will not benefit from the changes.
  
  

New Tax Credits Available

• Historic Homes Rehabilitation Credit (expanded): The credit for restoring historic homes has been extended to include more properties and increase credit access for qualifying renovation costs.
  
  
• Broadway Productions Tax Credit: A new credit is available for investments in pre- and post-Broadway productions that originate or tour in Connecticut, offering tax relief to arts investors and sponsors.
  
  
• Youth Development Organization Credit: Contributions to qualifying youth development organizations supporting nonprofits and community programs may now be eligible for a new tax credit.
  
  
• ABLE Account Contribution Credit: Taxpayers contributing to Connecticut ABLE accounts can now claim a credit for helping individuals with disabilities save for qualified expenses.
  
  

Pension Withholding Changes

• Withholding will no longer be mandatory starting January 1, 2025: Most pension and annuity payers will not be required to withhold Connecticut income tax from regular payments.
  
  
• Lump sum distributions may still be subject to it. Exceptions apply to lump-sum pension payments over $5,000, which may require withholding depending on your situation.
  
  

Forms You’ll Need 

Filing your Connecticut state income tax return requires the correct forms based on your residency status and income sources. The Connecticut Department of Revenue Services (DRS) provides all tax forms and instructions online, including specialized schedules for claiming credits and reporting additional tax obligations.

Form CT-1040 (Resident Return)

This is the standard income tax form for full-year Connecticut residents who lived in the state for the entire tax year.

• This form is used by Connecticut residents who have established legal residence in the state. If you maintained a permanent place of abode in Connecticut and were physically present for more than 183 days during the year, you must file using Form CT-1040.
  
  
• Required for most individual taxpayers: This form is used to file tax returns, calculate income taxes owed, report payments, and claim credits. It is the primary tax return form for individuals whose income comes from Connecticut sources.
  
  

Form CT-1040NR/PY (Nonresident or Part-Year Resident)

Nonresidents and part-year residents who earned income from Connecticut sources must use this form.

• For part-year residents and Connecticut nonresidents: If you moved in or out of Connecticut during the year or earned income from it while living elsewhere, use Form CT-1040NR/PY to file your state tax return.
  
  
• This form allocates income based on residency periods: This form helps taxpayers report only the portion of income subject to Connecticut income tax and apply any payments or credits appropriately.
  
  

Common Schedules

You may need to complete additional schedules to support your return, especially if you claim tax credits or report specific income types.

• Schedule 1 – Modifications to Federal Adjusted Gross Income: Adjusts your income for Connecticut tax purposes by adding or subtracting specific amounts from your federal AGI, including interest income or exempt Social Security benefits.
  
  
• Schedule 2 – Credit for Taxes Paid to Other States: Let's claim a credit if you paid income taxes to other states on income taxed by Connecticut. Avoid double taxation by filing this schedule if applicable.
  
  
• Schedule 3– Property Tax Credit: Used by Connecticut residents to claim a credit for property taxes paid on a primary residence or motor vehicle. The credit can reduce your state income tax.
  
  
• Schedule 4 – Individual Use Tax: Required if you made out-of-state or online purchases without paying sales tax. Connecticut taxpayers must report and pay use tax on those items.
  
  
• Schedule 5 – Charitable Contributions: Lets you contribute part of your refund to designated Connecticut charities. These contributions are voluntary but help support public services.
  
  

Extension & Credit Forms

The Connecticut Department of Revenue Services offers standard tax forms and forms for extensions and specialized credits.

• Form CT-1040 EXT – Extension Request: If you need more time to prepare your CT state return, use this form to request a filing extension. You must still pay any tax due by April 15 to avoid penalties.
  
  
• Schedule CT-EITC – Connecticut Earned Income Tax Credit: Use this form if you qualify for the federal EITC. The Connecticut version offers an additional credit equal to 40% of your federal credit.
  
  
• Schedule CT-PE – Pass-Through Entity Tax Credit: Used to claim a credit for taxes paid by certain LLCs or partnerships at the entity level. This credit can offset personal Connecticut income taxes owed.
  
  
• Form CT-6251 – Alternative Minimum Tax (AMT): If you paid the federal alternative minimum tax, you may also need to complete this form to calculate any corresponding Connecticut AMT obligation.

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Step-by-Step Filing Instructions

Before you file your Connecticut state income tax return, it’s essential to gather all relevant documents and understand the structure of the tax form. This section walks you through each part of the process so you can file your return accurately and avoid common errors.

Before You Begin

Organizing your tax documents in advance will help streamline the preparation process and ensure you meet all Connecticut Department of Revenue Services requirements.

• Collect federal tax forms and Connecticut documents: Gather your federal Form 1040, W-2s, 1099s, and any statements that show Connecticut income tax withheld. These documents are the foundation for completing your CT state return.
  
  
• Review records for payments, credits, and deductions: Have records ready for estimated tax payments, property tax bills, charitable contributions, and any credits you claim. This ensures you don’t miss deductions or underreport your income.
  
  

Step 1: Complete Taxpayer Information

The first part of your return includes personal information and your filing status.

• Use your correct filing status based on your federal return: Connecticut income tax filing status must generally match your federal filing status. However, special rules apply for married filing separately when one spouse is a part-year resident or nonresident.
  
  
• Include correct identification numbers: Enter your Social Security Number (SSN) or Individual Taxpayer Identification Number (ITIN) exactly as shown on your federal return. This is required for the state to process your return.
  
  

Step 2: Calculate Your Connecticut State Tax

Use your federal return as a starting point, then make Connecticut-specific adjustments.

• Start with your federal adjusted gross income (AGI): Enter the amount from Line 11 of your federal Form 1040 on Line 1 of the CT-1040. This number is the basis for determining your tax liability in Connecticut.
  
  
• Adjust for Connecticut modifications using Schedule 1: Schedule 1 allows you to add back or subtract income for Connecticut tax purposes. Examples include interest from non-Connecticut municipal bonds and exempt Social Security benefits.
  
  
• Compute your Connecticut adjusted gross income: Your Connecticut AGI is calculated by adjusting your federal AGI for state-specific modifications. This amount determines which tax table or formula applies to your income level.
  
  
• Use tax tables or calculation schedules: If your Connecticut AGI is under $102,000, use the tax tables provided by the revenue services. For higher incomes, use the tax calculation schedule to determine your tax.
  
  

Step 3: Apply Credits

Credits can reduce the amount of Connecticut income taxes you owe.

• Claim credit for taxes paid to other states using Schedule 2: If you paid income taxes to other states on the same income taxed by Connecticut, Schedule 2 helps you avoid double taxation by applying a credit.
  
  
• Determine if you owe Connecticut AMT: If you paid federal alternative minimum tax, complete Form CT-6251 to calculate any Connecticut AMT. This additional tax applies in certain higher-income situations.
  
  
• Apply the property tax credit using Schedule 3: You may be eligible for a credit of up to $300 for property taxes paid on your primary residence or motor vehicle. Use Schedule 3 to calculate this benefit.
  
  

Step 4: Report Use Tax

Connecticut residents are responsible for reporting and paying use tax on untaxed out-of-state purchases.

• Use Schedule 4 to report use tax: If you bought goods online or out of state without paying sales tax, report the total value on Schedule 4. This is required for Connecticut taxpayers.
  
  
• Penalties for failure to report can be significant: Not reporting required use tax may result in fines of up to $5,000, in addition to interest and late fees. Reporting accurately helps avoid enforcement actions.
  
  

Step 5: Enter Payments & Withholding

You must report all Connecticut tax payments, including any state tax withheld.

• Enter Connecticut tax withholding from W-2s and 1099s: Line 18 of the CT-1040 requires all sources of Connecticut withholding. Complete all fields (employer ID, income, and amount withheld), or the credit may be disallowed.
  
  
• Include estimated tax payments on Line 19: Report all state tax payments made during the year, including any made in 2025 for the 2024 tax year. These count toward your total payments.
  
  
• Calculate your CT Earned Income Tax Credit (EITC): If you qualified for the federal EITC, you may also claim the Connecticut version using Schedule CT-EITC. This credit is equal to 40% of your federal amount.

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How to File Your Return

If you're wondering how to file your Connecticut tax return, the Connecticut Department of Revenue Services (DRS) provides multiple options to file securely and efficiently. Whether you file electronically or by paper, selecting the right method helps avoid delays, processing errors, and potential penalties.

Electronic Filing Options

Filing electronically is the fastest and most accurate way to submit your state income tax return. It reduces common mistakes and speeds up your refund.

• Free online filing for Connecticut residents: The state’s official tax portal, myconneCT, allows eligible taxpayers to file their CT state return for free. You’ll need your prior Connecticut AGI or a valid Connecticut driver’s license or non-driver ID for access.
  
  
• Modernized e-File (MeF) for individual and business taxpayers: You can also file your return through IRS-authorized software providers that support Connecticut income taxes. These systems transmit your federal and state returns at the same time.
  
  
• Faster refunds and fewer filing errors: Electronic submissions go straight to the revenue services system, minimizing errors in taxpayer information, refund processing, and tax payments.
  
  

Third-Party Software vs. Professional Preparers

When preparing and submitting your tax return, you have options, including self-filing with software or using a professional.

• Using tax software for do-it-yourself filing: Many individuals prefer software that guides them through federal tax forms and then transitions into the Connecticut state tax portion. Having a basic income and a few credits or deductions is ideal.
  
  
• Tax professionals help with complex tax situations: If you’re a part-year resident, Connecticut nonresident, or have multiple income sources from other states, a tax preparer can help file tax returns accurately. This is especially useful for married filing separately or business owners. married couples

Paper Filing & Mailing Addresses

Although electronic filing is encouraged, Connecticut still accepts paper returns for those who prefer to file by mail.

• Use the correct mailing address based on payment status: If you include a check or money order with your return, send it to the address for payment. If you're due a refund or owe nothing, use the address for returns without payment.
  
  
• Mail for returns with payment enclosed:
  Department of Revenue Services
  PO Box 2977
  Hartford, CT 06104-2977
  
  
• Mail for returns without payment or with a refund request:
  Department of Revenue Services
  PO Box 2976
  Hartford, CT 06104-2976
  
  
• Mail for payments only (no return):
  Department of Revenue Services – Processing
  PO Box 5088
  Hartford, CT 06102-5088
  
  
• Payment instructions for checks or money orders: Make checks payable to “Commissioner of Revenue Services.” Include your Social Security Number and write “2024 Form CT-1040” on the memo line. Never send cash through the mail.
  
  

Filing your return accurately, whether by paper or electronically, ensures that the Connecticut Department of Revenue handles your state tax payments and refunds correctly. Always keep a copy of your income tax return and supporting documents for tax purposes in case the DRS needs to verify information in the future.

How to Make a Payment 

Whether you owe Connecticut state tax or make estimated payments, the Department of Revenue Services (DRS) offers several convenient payment options.

• Pay directly through myconneCT: Use myconneCT to authorize a one-time bank withdrawal. You can schedule the payment for any date on or before the filing deadline. This is the easiest way to pay your state income tax securely.
  
  

• Make payments online with a card: Connecticut accepts Visa, Mastercard, Discover, and American Express. A service fee applies, which you'll see before confirming your payment. This method is available through the DRS-approved processor.
  
  

• Traditional payment method for paper filers: If mailing a payment, make checks payable to "Commissioner of Revenue Services." Include your name, SSN, and “2024 Form CT-1040” on the memo line. Mail to the correct DRS address based on your tax return type.
  
  

• Know your due dates to avoid penalties: Regular returns and tax payments are due April 15, 2025. If you request an extension, your payment is still due on that date. Late payments incur a 10% penalty plus 1% monthly interest on unpaid balances.

Timely payments help avoid unnecessary fees and protect your standing with the Connecticut Department of Revenue. Always verify your payment was processed and keep records for the entire tax year.

How to Track Your Refund or Balance Due

After filing your Connecticut income tax return, you can easily track your refund or check your balance using online tools provided by the Connecticut Department of Revenue Services.

Online via myconneCT

• Check refund or balance anytime: Log in to myconneCT to view your refund status or account balance. You’ll need your SSN, tax year (2024), and refund amount.
  
  
• See your payment history and state tax balance: The portal lets you track past state tax payments, view tax filing activity, and even request a payment plan if you owe money.

By Phone

Call 860-297-5962 (or 800-382-9463 for calls outside Greater Hartford). Enter your SSN and refund amount to hear your refund status.

Processing Times & Tips

• Electronic returns process faster: Most e-filed returns are processed within a few weeks, while paper returns may take up to 12 weeks during peak tax season.
  
  
• Choose direct deposit for faster refunds: Refunds are quicker when you provide bank details. Paper checks take longer and may be delayed, especially for first-time filers.

Monitoring your refund or balance helps you stay informed and avoid surprises. For tax purposes, always keep a copy of your income tax return and confirmation of payments.

Frequently Asked Questions

What if I missed the April 15 deadline?

If you missed the deadline to file your Connecticut income tax return, file as soon as possible to minimize penalties and interest. The Connecticut Department of Revenue Services charges a 10% late filing penalty plus 1% monthly interest on any unpaid balance. You can still file through myconneCT and set up a payment plan if needed.

Can I e-file my Connecticut tax return for free?

Most residents can file their Connecticut state tax return for free using myconneCT, the Department of Revenue Services' official filing system. This option is available for individual taxpayers who meet eligibility requirements. You'll need access to your prior-year Connecticut AGI or a valid state-issued ID to verify your identity before e-filing.

What are the most commonly missed deductions or credits?

Many taxpayers overlook the Connecticut Earned Income Tax Credit (CT-EITC), the property tax credit for vehicles and primary residences, and income exclusions for Social Security and retirement pay. When preparing your income tax return, review available tax forms and schedules to ensure you claim eligible credits under Connecticut tax law.

How do I request an extension to file?

To request more time to file your Connecticut income tax return, submit Form CT-1040 EXT by April 15 through myconneCT. This gives you until October 15 to file. However, the extension only delays filing—not payment. Any Connecticut state tax you owe must still be paid by the original deadline to avoid interest and penalties.

Can I file jointly if one spouse moved during the year?

It depends on your residency status. If one spouse is a full-year resident and the other is a part-year resident or Connecticut nonresident, you may be required to file separately for Connecticut tax purposes. Even if you file jointly on your federal tax return, your CT state return may need to reflect separate Connecticut sources of income.

What if I discover a mistake after filing my return? 

If you find an error after submitting your Connecticut tax return, file an amended return using Form CT-1040X. You have up to three years from the original due date to correct mistakes. You can submit your amended CT state return electronically through myconneCT and include additional tax payments or documentation as needed for tax purposes.