Connecticut Income Tax Calculator (2026)

Connecticut Income Tax Overview

Connecticut levies a state income tax on the earnings of all residents and on the Connecticut-source income of non-residents. The tax is administered by the Connecticut Department of Revenue Services (DRS) and is filed on Form CT-1040 (residents) or Form CT-1040NR/PY (non-residents and part-year residents).

• Seven progressive brackets: 2%, 4.5%, 5.5%, 6%, 6.5%, 6.9%, and 6.99%
• Personal exemption instead of a standard deduction ($15,000 single; $24,000 MFJ)
• Social Security income is 100% exempt from Connecticut tax as of 2024
• No local city or county income taxes anywhere in Connecticut
• Military retirement pay is fully exempt from Connecticut income tax
• Property tax credit of up to $300 for eligible homeowners and renters
• Return due April 15; automatic 6-month extension available (tax still due April 15)
• Connecticut taxes capital gains as ordinary income at the same bracket rates

Connecticut is one of the few states with no local income tax, which means your state rate is your total state and local rate — an advantage for residents of high-cost cities like Stamford and Greenwich who might otherwise face city-level surcharges in other states.

2026 Connecticut Tax Brackets by Filing Status

Connecticut's seven income tax brackets are applied to Connecticut taxable income — your federal AGI adjusted for CT-specific items, minus your personal exemption. The brackets are doubled for married filing jointly filers (not for married filing separately).

Single / Married Filing Separately

Married Filing Jointly / Qualifying Surviving Spouse

Head of Household

Source: Connecticut Department of Revenue Services, 2026 Connecticut Income Tax Rate Schedule. Brackets are applied to Connecticut taxable income after the personal exemption is subtracted.

Connecticut Personal Exemption

Connecticut does not use a standard deduction like the federal return. Instead, each filer receives a personal exemption that is subtracted from Connecticut AGI to arrive at Connecticut taxable income. The exemption amounts for 2026 are:

How the Calculation Works

• Step 1 — Federal AGI: Start with your Adjusted Gross Income from your federal Form 1040. This is gross income minus federal adjustments like 401(k) contributions, IRA deductions, HSA contributions, and student loan interest.
• Step 2 — CT Modifications (additions): Add back any income excluded on the federal return but taxable in Connecticut. The most common addition is out-of-state municipal bond interest.
• Step 3 — CT Modifications (subtractions): Subtract income taxable federally but exempt in Connecticut, including Social Security benefits (100% exempt), qualifying pension and annuity income, US government interest, military retirement pay, and certain other items.
• Step 4 — Connecticut AGI: The result of Step 1 + Step 2 − Step 3 is your Connecticut Adjusted Gross Income.
• Step 5 — Subtract Personal Exemption: Subtract your personal exemption ($15,000 single, $24,000 MFJ, etc.) to arrive at Connecticut taxable income. If the exemption is more than your CT AGI, you owe $0.
• Step 6 — Apply Brackets: Apply the progressive bracket rates to your Connecticut taxable income in sequence — 2% on the first portion, 4.5% on the next, and so on up the table for your filing status.
• Step 7 — Subtract Credits: Reduce your tax by any credits you qualify for: property tax credit (up to $300), credit for income taxes paid to another state, earned income tax credit, and others.
• Step 8 — Compare to Withholding: If your employer withheld more CT tax from your paychecks than you owe, you get a refund. If less, you owe the difference by April 15.

Worked Examples

Social Security & Retirement Income in Connecticut

Connecticut made a major change for retirees beginning with the 2024 tax year: Social Security benefits are now 100% exempt from Connecticut income tax, regardless of income level. This eliminated the previous partial exemption that had phased out for higher-income retirees.

The combination of the full Social Security exemption, the pension exemption for moderate-income retirees, and no local income taxes makes Connecticut significantly more retirement-friendly than its reputation as a high-tax state might suggest. Many Connecticut retirees living on Social Security plus a modest pension pay little or no Connecticut income tax.

Key Connecticut Income Tax Credits

• Property Tax Credit (up to $300): Available to resident homeowners and renters who paid qualifying property taxes on their primary Connecticut residence. The credit phases out at higher income levels and is unavailable to dependents claimed on another return. Claim on Schedule CT-1040 PTC.
• Credit for Income Taxes Paid to Another State: If you earn income in another state and pay income tax there, Connecticut generally allows a credit to prevent double taxation. The credit equals the smaller of the CT tax attributable to the out-of-state income or the actual tax paid to the other state.
• Connecticut Earned Income Tax Credit (CT EITC): Equal to 41.5% of the federal Earned Income Tax Credit for 2026. Refundable, meaning it can result in a refund even if you owe no CT tax. Targeted at low-to-moderate income workers.
• Child Tax Rebate: Connecticut periodically issues child tax rebates to eligible families, though these are subject to annual legislative action and budget availability.
• Angel Investor Tax Credit: Available to investors who provide seed capital to certain Connecticut small businesses; requires DRS certification.
• Historic Homes Rehabilitation Tax Credit: For eligible rehabilitation costs on owner-occupied historic homes; subject to limits and DRS certification.

Connecticut vs. Neighboring States

Connecticut residents often compare their state income tax burden to neighboring states — particularly New York, Massachusetts, and Rhode Island. Here is how the 2026 income tax landscape compares:

Compared purely on top marginal rates, Connecticut's 6.99% is lower than New York's 10.9% and New Jersey's 10.75%, and roughly comparable to Rhode Island (5.99%). Connecticut's biggest structural advantage over New York is the absence of any local income tax — a New York City resident pays state plus city rates totaling nearly 15% at the top, while a Stamford resident — even one commuting into New York — is subject only to Connecticut's rates on Connecticut-sourced income.

Who Must File a Connecticut Income Tax Return

• Full-year residents must file Form CT-1040 if their Connecticut AGI exceeds their personal exemption amount — or if they had any Connecticut income tax withheld that they want refunded.
• Part-year residents (moved into or out of Connecticut during the year) must file Form CT-1040NR/PY and pay CT tax on the income earned while a CT resident, plus CT-source income earned as a non-resident.
• Non-residents with Connecticut-source income (wages from a CT employer, CT rental income, CT business income) must file Form CT-1040NR/PY.
• Minimum filing threshold: A single filer with CT AGI of $15,000 or less generally owes no CT tax (because the personal exemption eliminates their taxable income), but may still want to file to claim a refund of withheld taxes or the CT Earned Income Tax Credit.

Filing Tips & Deadlines

• Original return due date: April 15, 2026 (for the 2025 tax year)
• Automatic extension: Connecticut grants an automatic 6-month extension to October 15, 2026 — no form is needed if you've paid at least 90% of your tax due by April 15. Underpayment after April 15 accrues interest.
• Estimated tax payments: Required if you expect to owe more than $1,000 in CT tax not covered by withholding. Due quarterly: April 15, June 15, September 15, January 15.
• Filing online: The Connecticut DRS offers free e-filing at myconneCT, the state's online tax portal. Filing electronically generally results in faster refunds.
• Withholding verification: Use the Connecticut DRS withholding calculator to make sure your employer is withholding the right amount, especially if you had a major income change, got married, or had a child.
• Keep records for three years: Connecticut's standard statute of limitations for income tax assessments is three years from the filing date, though it extends to six years if more than 25% of income was omitted.

Ways to Reduce Your Connecticut Income Tax

• Maximize pre-tax retirement contributions. Traditional 401(k), 403(b), and IRA contributions reduce your federal AGI, which flows directly into a lower Connecticut AGI and a lower CT tax bill. In 2026, the 401(k) contribution limit is $23,500 ($31,000 if age 50+).
• Contribute to a Health Savings Account (HSA). HSA contributions are deductible from federal AGI and therefore reduce CT taxable income. For 2026, the HSA limit is $4,300 (self-only) or $8,550 (family).
• Use Connecticut's CHET 529 plan for education savings. Connecticut residents who contribute to the Connecticut Higher Education Trust (CHET) 529 plan can deduct contributions of up to $10,000 (single) or $20,000 (MFJ) per year from their Connecticut AGI — reducing CT taxable income directly.
• Claim the property tax credit. If you own or rent a home in Connecticut, make sure to claim the up-to-$300 property tax credit. It is a direct credit against tax owed, not just a deduction.
• Claim the CT Earned Income Tax Credit. The refundable CT EITC (41.5% of the federal EITC) is one of the most valuable and often overlooked credits for working households earning under about $65,000.
• Donate to a CT Neighborhood Assistance Act program. Certain qualifying charitable contributions to approved state programs can generate a Connecticut credit equal to 60%–100% of the donation — substantially more valuable than a standard deduction.
• Ensure pension income qualifies for CT exemption. If you are a retiree with CT AGI near the $75,000 (single) or $100,000 (MFJ) pension exemption threshold, consider whether shifting certain income to a different year could keep you below the threshold and eliminate your CT tax bill entirely.

Common Mistakes on Connecticut Income Tax Returns

• Forgetting the Social Security exemption. Some filers still manually add Social Security income to their Connecticut return out of habit from prior years. As of 2024, it is 100% exempt — do not include it in CT income.
• Using the wrong filing status. Connecticut accepts all standard federal filing statuses but does not recognize common-law marriage. Married couples registered under Connecticut law must file jointly or separately — not as single.
• Failing to report out-of-state municipal bond interest. Interest on bonds issued by states other than Connecticut is exempt federally but taxable in Connecticut. It must be added back on Schedule 1 of Form CT-1040.
• Missing the CHET 529 deduction. Contributions to Connecticut's own 529 plan (CHET) are deductible from CT AGI; contributions to another state's 529 plan are not.
• Assuming New York commuters owe only CT tax. If you are a Connecticut resident working for a New York employer, you may owe New York tax as well, and need to properly claim the CT credit for taxes paid to New York to avoid double taxation.
• Not filing an estimated return and getting penalized. If you are self-employed or have significant investment income, Connecticut expects quarterly estimated payments. Missing them triggers underpayment penalties even if you pay in full by April 15.
• Claiming the property tax credit without qualifying. The credit is available only for property taxes paid on your primary Connecticut residence. Taxes on investment property, vacation homes, or vehicles do not qualify.

Glossary of Connecticut Income Tax Terms

Connecticut AGI (CT AGI)

Your federal Adjusted Gross Income, modified by Connecticut-specific additions (like out-of-state municipal bond interest) and subtractions (like Social Security, qualifying pension income, and US government interest).

Connecticut Taxable Income

CT AGI minus your Connecticut personal exemption. This is the amount on which your bracket tax rates are applied.

Personal Exemption

Connecticut's equivalent to a standard deduction. A fixed dollar amount subtracted from CT AGI to arrive at CT taxable income. Amounts are $15,000 (single), $24,000 (MFJ), $12,000 (MFS), and $19,000 (HoH). Phases out for higher earners.

Form CT-1040

The primary Connecticut individual income tax return filed by full-year residents. Filed with the Connecticut Department of Revenue Services.

Form CT-1040NR/PY

The Connecticut income tax return for non-residents and part-year residents who had Connecticut-source income during the year.

Effective Tax Rate

Your total Connecticut income tax divided by your total gross income (or CT AGI), expressed as a percentage. Always lower than your marginal (top bracket) rate because lower brackets apply first.

Marginal Tax Rate

The rate that applies to your last dollar of Connecticut taxable income — the top bracket you have reached. This is the rate relevant for planning decisions about earning extra income.

Connecticut DRS

The Connecticut Department of Revenue Services — the state agency that administers, processes, and audits Connecticut income tax returns.

CHET (Connecticut Higher Education Trust)

Connecticut's state-sponsored 529 college savings plan. Contributions by Connecticut residents are deductible from Connecticut AGI up to $10,000 per filer per year.

myconneCT

The Connecticut DRS's online portal for filing returns, making payments, and managing your Connecticut tax account.

Frequently Asked Questions

Q: What is the Connecticut income tax rate for 2026?

A: Connecticut uses seven progressive tax brackets for 2026. The rates are 2%, 4.5%, 5.5%, 6%, 6.5%, 6.9%, and 6.99%. The bracket thresholds are higher for married filing jointly filers. For a single filer, the 2% rate applies to the first $10,000 of CT taxable income and the top rate of 6.99% applies only to CT taxable income above $500,000.

Q: Does Connecticut tax Social Security income in 2026?

A: No. Connecticut fully exempts all Social Security benefits from state income tax, a change that took effect for the 2024 tax year and continues into 2026. There is no income limit on this exemption — even high-income retirees pay no CT tax on Social Security.

Q: What is the Connecticut standard deduction for 2026?

A: Connecticut does not use a standard deduction. Instead, it provides a personal exemption: $15,000 for single filers, $24,000 for married filing jointly, $12,000 for married filing separately, and $19,000 for head of household. This exemption phases out at higher income levels.

Q: When is the Connecticut income tax return due?

A: The Connecticut income tax return for the 2025 tax year is due April 15, 2026. An automatic six-month extension to October 15, 2026 is available without filing a form, provided you pay at least 90% of your estimated tax liability by April 15. Any balance owed after April 15 accrues interest.

Q: Does Connecticut tax pension and retirement income?

A: Connecticut offers a 100% exemption on pension and annuity income for filers whose CT AGI is $75,000 or below (single) or $100,000 or below (married filing jointly). Military retirement pay is fully exempt at all income levels. 401(k) and traditional IRA distributions are generally taxable; qualified Roth IRA distributions are not.

Q: Does Connecticut have local income taxes?

A: No. Connecticut has no local or municipal income taxes. Whether you live in Hartford, Bridgeport, Stamford, New Haven, Waterbury, or any other Connecticut city or town, you pay only the Connecticut state income tax rate — there is no additional city-level tax on top of it.

Q: Is Connecticut a good state for high earners compared to New York?

A: For high earners, Connecticut's top rate of 6.99% is meaningfully lower than New York State's 10.9%. More importantly, Connecticut has no local income tax, while New York City residents pay an additional NYC income tax of up to 3.876%, pushing their combined state and local rate above 14%. Many finance and hedge fund professionals choose to live in Fairfield County (Greenwich, Westport, Darien) specifically to reduce their income tax burden compared to living in New York City.

Q: How do I calculate my Connecticut paycheck withholding?

A: Connecticut employers use withholding tables published by the DRS, based on the employee's Form CT-W4 elections. If you want to verify your withholding is correct, use the Connecticut DRS withholding calculator at portal.ct.gov/DRS or enter your full-year income into our calculator above and compare the result to your year-to-date withholding on your pay stub.