Connecticut taxes

Connecticut taxes personal income at 2% to 6.99%. A sole proprietor owes no separate business tax. An LLC, limited partnership or LLP pays an annual report fee of $80, and a corporation pays $150. C corporations also pay 7.5% corporation business tax, never less than $250. Partnerships and S corporations can choose to pay tax at the business level, but they do not have to.

Personal income tax

Connecticut residents file Form CT-1040. Rates rise in steps from 2% to 6.99%. There is no standard deduction. Instead there is a personal exemption that shrinks as income rises and disappears partway up.

At higher incomes Connecticut takes back the benefit of its lower rates through extra add-back and recapture amounts, so the tax can be more than the rate steps alone suggest. Lower-income filers get a personal tax credit worth up to 75% of their tax, which phases out as income rises.

Social Security is not taxed below $75,000 of income ($100,000 married filing jointly). Above that, at most 25% of the federally taxable amount is taxed. Connecticut also has a property tax credit and an earned income tax credit.

Return

Form CT-1040

Rates, single or married filing separately

2% up to $10,000, 4.5% above $10,000, 5.5% above $50,000, 6% above $100,000, 6.5% above $200,000, 6.9% above $250,000, 6.99% above $500,000

Rates, married filing jointly

2% up to $20,000, 4.5% above $20,000, 5.5% above $100,000, 6% above $200,000, 6.5% above $400,000, 6.9% above $500,000, 6.99% above $1,000,000

Rates, head of household

2% up to $16,000, 4.5% above $16,000, 5.5% above $80,000, 6% above $160,000, 6.5% above $320,000, 6.9% above $400,000, 6.99% above $800,000

Personal exemption, single

$15,000, falling by $1,000 for each $1,000 of income over $30,000

Personal exemption, married filing jointly

$24,000, falling by $1,000 for each $1,000 of income over $48,000

Personal exemption, head of household

$19,000, falling by $1,000 for each $1,000 of income over $38,000

Personal exemption, married filing separately

$12,000, falling by $1,000 for each $1,000 of income over $24,000

Pensions, 401(k) and non-Roth IRA payouts

Not taxed when income is under $100,000 ($150,000 married filing jointly)

Connecticut Teachers' Retirement pay

50% is not taxed, at any income

Sole proprietor

A sole proprietor with no LLC files no annual report with the Connecticut Secretary of the State and owes no fee for the business itself.

Your business profit is taxed on your own Form CT-1040, at the personal rates above. Forming an LLC would start the $80 a year.

Single-member LLC

Every Connecticut LLC files an annual report with the Secretary of the State and pays $80, each year between January 1 and March 31, whatever it earned. That is the only yearly charge on a single-member LLC.

The $250 Business Entity Tax Connecticut used to charge was abolished from January 1, 2020. The $250 minimum corporation business tax applies to corporations, not to an LLC. The LLC's profit is taxed on your own Form CT-1040.

Partnership

A Connecticut partnership files Form CT-1065/CT-1120SI, the pass-through entity return. The profit passes through to the partners, who report it on their own returns.

An LLC, limited partnership or limited liability partnership also files an annual report and pays $80, whatever it earned. An LLC files each year between January 1 and March 31; the others file on the anniversary of their formation.

The partnership can choose to pay the pass-through entity tax of 6.99% on its Connecticut income, instead of leaving that tax to the partners. It was required until 2024 and is now optional. The choice is made in writing each year by the filing deadline and cannot be undone once made.

S corporation

A Connecticut S corporation files Form CT-1065/CT-1120SI, the same return as a partnership. The profit passes through to the shareholders, who report it on their own returns.

It files an annual report and pays $150, whatever it earned, due on the anniversary of formation rather than a date shared with other businesses. Like a partnership, it can choose to pay the 6.99% pass-through entity tax, and the choice cannot be undone.

C corporation

A C corporation files Form CT-1120 and pays the corporation business tax: 7.5% of the net income apportioned to Connecticut, and never less than $250, even in a year it lost money. A corporation selling into other states counts only its Connecticut share, measured by sales, with each sale counted where the customer is.

Connecticut also works out a tax on capital, 2.1 mills per dollar for 2025 capped at $1,000,000, and charges whichever is larger. A company with a lot of capital and a small profit pays the capital one.

The $150 annual report fee goes to the Secretary of the State on the anniversary of formation, on top of the tax.

Return

Form CT-1120

Corporation business tax

7.5% of Connecticut net income, minimum $250

Tax on capital

2.1 mills per dollar for 2025, capped at $1,000,000, charged if larger

Surtax

10% of the tax, only at $100,000,000 of total income or for combined unitary groups

Multi-state profit

Connecticut sales over total sales, counted where the customer is

Annual report fee

$150, due on the anniversary of formation

Estimate your state tax

Pick your business type and enter this year's numbers to see the state business tax Connecticut charges. It assumes all your sales are in Connecticut.

An estimate for planning, not tax advice.

Sources

• Connecticut Form CT-1040 Instructions (Rev. 12/25)
• portal.ct.gov DRS Corporation Business Tax Information
• portal.ct.gov Form CT-1120 (12/2025), Schedule C: "Minimum Tax $250"
• portal.ct.gov DRS Pass-Through Entity Tax Information
• business.ct.gov Domestic Annual Report Forms and Fees
• portal.ct.gov Form CT-1120 (12/2025), Schedule A line 6, Schedule B line 6 and Schedule C
• portal.ct.gov Form CT-1120 Instructions (12/2025), Schedule B
• portal.ct.gov SN 2017(1), Single-Sales Factor Apportionment and Market-Based Sourcing

Last reviewed August 2026.