Connecticut Estimated Tax Deadlines — 2026
2026 estimated tax payment deadlines for each quarter. Avoid penalties by filing on time.
Connecticut residents who work for themselves face a unique combination of federal and state tax obligations. This page provides state-specific guidance for estimated tax deadlines in Connecticut for the 2026 tax year, drawing on IRS publications and Connecticut tax authority data.
Connecticut imposes a state income tax with 7 tax brackets and a top marginal rate of 7%. The state standard deduction is not applicable, and self-employed residents must pay both federal and state income taxes on their net earnings. Forming an LLC in Connecticut costs $120 in state filing fees. LLCs in Connecticut must pay an annual report fee of $80. The state sales tax rate in Connecticut is 6%, which applies to most business purchases and sales of taxable goods. Quarterly estimated tax payments are due April 15, June 16, September 15, and January 15 in Connecticut. Understanding these obligations before you file prevents penalties and identifies legitimate savings opportunities.
Quick Connecticut Tax Estimate
Based on Connecticut's tax rates for 2026. Sample calculation for $80,000 net profit.
Connecticut Tax Facts — 2026
How to Use This Calculator
Review the Connecticut-specific information on this page, then use the linked calculators to compute your personalized estimates. Enter your income and expenses, select Connecticut, and review your results. Cross-check key figures against the official Connecticut tax authority website linked in the resources section.
Why Getting This Right Matters
Tax mistakes cost Connecticut self-employed individuals real money — penalties, interest, and missed deductions. Accurate state-specific guidance means paying exactly what you owe, claiming every deduction available, and avoiding costly surprises. The 8% IRS underpayment rate plus Connecticut state penalties make accuracy a financial necessity.
Connecticut Income Tax Brackets (2026)
| Tax Rate | From | To |
|---|---|---|
| 2% | $0 | $10,000 |
| 4.5% | $10,001 | $50,000 |
| 5.5% | $50,001 | $100,000 |
| 6% | $100,001 | $200,000 |
| 6.5% | $200,001 | $250,000 |
| 6.9% | $250,001 | $500,000 |
| 7% | $500,001 | No limit |