Connecticut Income Tax Calculator 2026

How Connecticut Income Tax Calculator Works

Calculate your Connecticut income tax (up to 6.99%) plus federal tax. See combined brackets, effective rate, and take-home pay. and. Enter your values into the form above and the calculator processes them instantly in your browser — no data is sent to any server.

Connecticut Income Tax: Graduated Brackets Up to 6.99%

Connecticut uses a progressive income tax system with 7 brackets. Rates range from 3.0% to 6.99%, with higher income taxed at higher rates. Connecticut also applies a tax on capital gains and has a personal tax credit for lower-income filers.

Like federal taxes, Connecticut's system is marginal — only the income within each bracket is taxed at that bracket's rate. Combined with federal taxes (10%–37%), Connecticut residents can face a total marginal rate of up to 43.99% on their highest dollars of income.

Connecticut Tax Brackets for 2026 (Single Filer)

The Connecticut income tax brackets for single filers are:

• 3.0% on income from $0 to $10,000
• 5.0% on income from $10,000 to $50,000
• 5.5% on income from $50,000 to $100,000
• 6.0% on income from $100,000 to $200,000
• 6.5% on income from $200,000 to $250,000
• 6.9% on income from $250,000 to $500,000
• 6.99% on income over $500,000

Your marginal rate is the rate on your last dollar of income. Your effective rate (total tax divided by total income) is always lower because of the progressive structure.

Tips to Lower Your Connecticut Tax

Maximize pre-tax retirement contributions to reduce both federal and Connecticut taxable income. The 2026 401(k) limit is $24,500 ($32,500 with catch-up for age 50+). If Connecticut conforms to federal deductions, your standard deduction and itemized expenses also reduce your state tax liability.

Tips for Getting Accurate Results

For the most accurate results, use up-to-date numbers from official sources. Double-check your inputs before calculating — small errors in the starting values can lead to significantly different outputs. If you are comparing scenarios, keep all variables the same except the one you are testing. Save or screenshot your results for future reference. This calculator uses standard formulas and is designed to give you a reliable quick estimate, though professional advice may be needed for complex situations.

Connecticut Income Tax Calculator: Pass-Through Entity Tax (PET) Credit Explained

If you receive income through a Connecticut S-corp, LLC, or partnership, the Pass-Through Entity Tax (PET) materially changes your personal Connecticut income tax owed. Per the CT DRS Pass-Through Entity Tax overview, the entity pays Connecticut tax at the 6.99% top rate on income attributable to CT, and you receive a personal credit equal to 87.5% of your share of that PET. For a $200,000 K-1 share, the entity pays $13,980 and you claim a $12,233 credit on your CT-1040 — neutralizing most of the double taxation. This is one of the few states where PET still nets a federal tax benefit (the entity-level deduction beats the $10,000 SALT cap workaround). This calculator's output is the pre-PET state liability; subtract your PET credit if you are a pass-through owner. Updated 2026-06-19.

Connecticut Income Tax Calculator: Estimated Payments for Self-Employed and Investors (2026)

If you have non-wage income — 1099, rental, capital gains, or pass-through entity distributions — Connecticut requires quarterly estimated payments via Form CT-1040ES. Use the connecticut income tax calculator above to project your full-year liability, divide by 4 for each quarter. 2026 due dates: April 15 (Q1), June 16 (Q2), September 15 (Q3), January 15, 2027 (Q4) — same as federal Form 1040-ES. CT DRS safe-harbor: pay 100% of last year's CT tax or 90% of current-year tax in equal installments to avoid the underpayment penalty. Connecticut adds a wrinkle: if your prior-year AGI was over $150,000 ($75,000 if MFS), the safe-harbor jumps to 110% of last year. Investor example: $15,000 LTCG at 6.5% CT rate = $975 CT tax → $244 per quarterly CT-1040ES voucher per the CT DRS Personal Income Tax page. Updated 2026-06-27.

Connecticut Income Tax Calculator: Worked Example for an $80,000 Salary in 2026

Walk through a CT resident scenario: $80,000 single-filer gross. The first $10,000 taxes at 3.0% = $300. The next $40,000 (10K–50K bracket) at 5.0% = $2,000. The next $30,000 (50K–80K, inside the 5.5% bracket) = $1,650. Total CT state tax = $3,950, an effective rate of 4.9%. Connecticut also offers a personal tax credit phase-out for AGI under $48,000 single. Per CT DRS Personal Income Tax 2026, the 2024 tax cut reduced the lowest two brackets (3.0% → 2.0% and 5.0% → 4.5%) for most filers — a permanent reduction worth roughly $250 on an $80K salary. Stack federal tax (~$10,852 single in 2026), FICA ($6,120), and your take-home is approximately $58,768 (73.5% retention).

Connecticut Income Tax Calculator: 2026 Retirement and Social Security Exclusion

Connecticut has phased in one of the most retiree-friendly reforms on the East Coast. Per the CT DRS Personal Income Tax page, Social Security benefits are 100% CT-tax-exempt for single filers with federal AGI under $75,000 and joint filers under $100,000, with a phase-down above those AGIs. Additionally, 100% of pension and annuity income (traditional IRA, private, and government pensions) is exempt for single filers under $75K AGI / joint under $100K AGI — completing a multi-year phase-in that started in 2019. A retired CT couple with $28,000 Social Security, $22,000 pension, and $10,000 traditional IRA withdrawal (federal AGI $60,000) owes $0 in Connecticut state income tax because SS + pension exclusions cover everything except the IRA, which is under the CT personal exemption. Above the AGI thresholds, exemptions phase out $2,500 per $5,000 of excess AGI. Run the connecticut income tax calculator with your AGI to see which zone you fall in. Updated 2026-07-04.

Income Tax Calculator Connecticut: 2026 Filing Deadlines and Withholding Verification

The 2026 Connecticut income tax filing deadline is April 15, 2027 — the same day as federal Form 1040. Per the CT DRS Individual Filing Information page, six-month extensions via Form CT-1040 EXT push the deadline to October 15, 2027, but an extension to file is NOT an extension to pay — full estimated tax must be paid by April 15 to avoid the 1% monthly late-payment interest plus 10% penalty. Compare this income tax calculator connecticut output against your 2026 W-2 Box 17 (state withholding); a gap larger than $500 means you should file a new CT-W4 with your employer for 2027. Retirees receiving 1099-R distributions should confirm the CT box shows correct withholding after the retirement exclusion applies. Last updated: 2026-07-15.