Finance · Connecticut · Tax year 2026

Connecticut Self-Employment Tax Calculator 2026

On $100,000 of 2026 self-employment profit, a single Connecticut sole proprietor with no other income owes about $26,926: $14,130 of self-employment tax, $8,235 of federal income tax, and $4,561 of Connecticut income tax. That is 26.9% of profit, or $6,732 for each quarterly estimated payment.

Against its neighbors, the same $100,000 of profit costs $119 more in Massachusetts and $1,693 less in Rhode Island.

State income tax: 2% to 6.99%
Connecticut tax on $100,000: $4,561
National rank: #9 highest of 51
Set aside on $100,000: 26.9%
State estimated payments: Form CT-1040ES
LLC filing fee: $120
State sales tax: 6.35%

State

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Net self-employment profit (2026)

Other income (W-2 wages, spouse, interest)

More options

Retirement + health insurance deductions

Local income tax rate (optional)

Service business (consulting, law, health, accounting, financial services, performing arts). Only matters for the QBI deduction at higher incomes.

Enter your net profit — revenue minus business expenses — to see how much to set aside and what to pay each quarter.

A 2026 planning estimate using the standard deduction, not a tax return: it ignores credits, itemized deductions, and AMT. All calculations happen in your browser. Nothing is stored.

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Connecticut self-employment tax at common profit levels

2026 estimates for a single filer with no other income, using the standard deduction and no retirement or health insurance deductions. "Set aside" is the share of profit to move into a tax account; "Quarterly" is each of the four estimated payments.

Profit	SE tax	Federal income tax	Connecticut tax	Total	Set aside	Quarterly
$40,000	$5,652	$1,775	$997	$8,424	21.1%	$2,106
$60,000	$8,478	$3,559	$2,085	$14,122	23.5%	$3,531
$80,000	$11,304	$5,344	$3,439	$20,087	25.1%	$5,022
$100,000	$14,130	$8,235	$4,561	$26,926	26.9%	$6,732
$150,000	$21,194	$16,413	$7,539	$45,147	30.1%	$11,287
$250,000	$29,851	$36,509	$14,259	$80,619	32.2%	$20,155

Married filing jointly

The same profit, earned by one spouse filing jointly with no other household income.

Profit	SE tax	Federal income tax	Connecticut tax	Total	Set aside	Quarterly
$40,000	$5,652	$398	$171	$6,221	15.6%	$1,555
$60,000	$8,478	$1,885	$1,160	$11,523	19.2%	$2,881
$80,000	$11,304	$3,550	$2,561	$17,415	21.8%	$4,354
$100,000	$14,130	$5,335	$3,314	$22,778	22.8%	$5,695
$150,000	$21,194	$9,795	$6,567	$37,557	25.0%	$9,389
$250,000	$29,573	$25,154	$12,263	$66,991	26.8%	$16,748

How Connecticut taxes self-employment income

Connecticut starts from federal adjusted gross income (after the deduction for half of self-employment tax), then applies its own deductions, exemptions, and credits.

Standard deduction: $0 (none)
Personal exemption: $15,000 single, $24,000 joint, $19,000 head of household
Top rate: 6.99%; your bracket on $100,000 of profit is 5.5%.

2026 Connecticut income tax brackets (single)

Taxable income over	Up to	Rate
$0	$10,000	2%
$10,000	$50,000	4.5%
$50,000	$100,000	5.5%
$100,000	$200,000	6%
$200,000	$250,000	6.5%
$250,000	$500,000	6.9%
$500,000	and up	6.99%

2026 Connecticut brackets (married filing jointly)

Taxable income over	Up to	Rate
$0	$20,000	2%
$20,000	$100,000	4.5%
$100,000	$200,000	5.5%
$200,000	$400,000	6%
$400,000	$500,000	6.5%
$500,000	$1,000,000	6.9%
$1,000,000	and up	6.99%

Connecticut vs its neighbors

The same $100,000 of 2026 profit for a single sole proprietor, run through each state's rules. Federal tax is the same everywhere, so the difference is state income tax. Against its neighbors, the same $100,000 of profit costs $119 more in Massachusetts and $1,693 less in Rhode Island.

State	State income tax	Total tax	Set aside	vs Connecticut
Connecticut	$4,561	$26,926	26.9%	—
Massachusetts	$4,680	$27,045	27.0%	+$119
New York	$4,443	$26,807	26.8%	−$119
Rhode Island	$2,868	$25,233	25.2%	−$1,693

How the gap changes with profit

Extra tax (+) or savings (−) for a single filer if the same business were based in each of its neighbors instead of Connecticut.

Profit	Massachusetts	New York	Rhode Island
$40,000	+$683	+$413	−$220
$60,000	+$595	+$329	−$611
$80,000	+$241	−$21	−$1,268
$100,000	+$119	−$119	−$1,693
$150,000	−$359	+$5	−$2,519
$250,000	−$2,079	+$69	−$4,287

What's different about Connecticut for the self-employed

Includes Connecticut's personal tax credit, the 2% rate phase-out, and its benefit recapture for higher incomes.
No local income taxes. LLCs file an $80 annual report.
Registering to collect Connecticut sales and use tax costs $100, and a separate Sales and Use Tax Permit is needed for each location (including flea markets and craft shows).
There are no local sales taxes in Connecticut; the 6.35% statewide rate applies to most goods and taxable services.

Connecticut estimated payments and deadlines

Connecticut collects its own estimated income tax with Form CT-1040ES, separately from the IRS. Required if your Connecticut income tax after withholding and any pass-through entity tax credit is $1,000 or more, and you expect withholding (plus PE tax credit) to be less than your required annual payment (the smaller of 90% of 2026 tax or 100% of 2025 tax).

Installment	Connecticut due date	Share of the year	Federal due date
Q1	April 15, 2026	25%	April 15, 2026
Q2	June 15, 2026	25%	June 15, 2026
Q3	September 15, 2026	25%	September 15, 2026
Q4	January 15, 2027	25%	January 15, 2027

The 2026 Connecticut income tax return is due April 15, 2027.

File and pay through the Connecticut Department of Revenue Services.

LLC fees and sales tax in Connecticut

Forming an LLC: $120 state filing fee.
Annual Report: $80, every year, due between January 1 and March 31.
Sales tax: 6.35% statewide. Use the Sales Tax Calculator to price a sale.

A single-member LLC is taxed exactly like a sole proprietorship unless it elects S or C corporation status, so the self-employment tax figures on this page apply either way.

Connecticut self-employment tax FAQs

How much should I set aside for taxes if I'm self-employed in Connecticut?

For a single filer with no other income, about 23.5% of profit at $60,000, 26.9% at $100,000, and 30.1% at $150,000 for 2026, covering self-employment tax, federal income tax, and Connecticut income tax. Enter your own numbers in the calculator for a personal figure.

Does Connecticut tax self-employment income?

Yes. Connecticut taxes self-employment profit as ordinary income at 2% to 6.99%. Connecticut starts from federal adjusted gross income (after the deduction for half of self-employment tax), then applies its own deductions, exemptions, and credits.

When are Connecticut estimated tax payments due for 2026?

April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027, using Form CT-1040ES. Required if your Connecticut income tax after withholding and any pass-through entity tax credit is $1,000 or more, and you expect withholding (plus PE tax credit) to be less than your required annual payment (the smaller of 90% of 2026 tax or 100% of 2025 tax).

How much does an LLC cost in Connecticut?

The state filing fee to form an LLC is $120. Annual Report: $80, every year, due between January 1 and March 31. A single-member LLC is still taxed like a sole proprietorship for federal purposes, so the self-employment tax figures above apply.

Sources and method

Computed with the Self-Employment Tax Calculator's 2026 engine and Connecticut's rules from the sources below. Planning estimates, not a return. Last checked 2026-10-08.