How much Connecticut income tax will I owe for 2025?

Estimate Connecticut income tax for 2025 or 2026 by entering Connecticut taxable income, filing status, and residency allocation. The calculator applies Connecticut income tax rates to estimate tax due and effective rate so you can plan payments or withholding.

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How this calculation works

  • Uses Connecticut taxable income and filing status to estimate state tax.
  • Applies Connecticut rates for the selected year.
  • Calculates estimated tax due and effective rate.

Common mistakes and caveats

  • Part-year and nonresident filers should prorate Connecticut-source income.
  • Credits and special deductions can change the final result.
  • Local taxes are not included.

FAQ

Should I enter Connecticut taxable income or total income?

Use Connecticut taxable income from your return. If you only know total income, estimate deductions first.

Last updated & sources

Last updated January 27, 2026.

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TaxGuide Pro provides free state and federal tax calculators for individuals, freelancers, and small businesses.

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