Connecticut Income Tax Calculator 2025
Connecticut levies a progressive personal income tax with a top marginal rate of 6.99% for the 2025 tax year, applied across multiple brackets (some states use different brackets for single and joint returns). This calculator applies the live 2025–2026 brackets to the state taxable income you enter — the state standard deduction and exemptions are shown for reference, so subtract them first — and produces both your effective and marginal rate so you can compare Connecticut side-by-side before filing. Connecticut uses a domicile + permanent place of abode test, similar to NY; see CT-1040 instructions. Use it alongside our federal calculator and the neighboring-state comparison below to see your full 2025–2026 picture.
State tax is where 'simple' becomes complicated fast. Nine states tax no wage income at all — New Hampshire joined them outright when its interest-and-dividends tax ended January 1, 2025 — and Washington taxes only certain capital gains. The rest each have their own brackets, credits, conformity quirks with federal law, and reciprocity rules with neighbors. Pick the wrong residency date and you'll file two part-year returns.
Real-world scenario
Software engineer moves from California to Texas mid-year
$220K salary, moves July 1. California taxes the $110K earned while a resident (~$10K state tax). Texas: $0. But California also taxes any RSUs that vested while she was a CA resident, even if she moved before exercising. If she sold ISO stock in December while a TX resident, CA still claims a piece based on the workdays-in-CA allocation during the grant period.
The part most people miss
Domicile vs. residency is the audit battleground. California in particular runs aggressive residency audits on high earners who 'move' to Texas, Florida, or Nevada. They look at where your dentist is, where your dog is licensed, where your driver's license was issued, and how many days you spent in the state. California has no 183-day bright line — its test is domicile plus facts and circumstances (the mechanical 183-day/permanent-abode test is New York's); the soft factors decide.
Calculate Your Connecticut State Tax
Enter your state taxable income to see your estimated Connecticut state tax before credits (bracket math on the income you enter — state credits are not modeled)
2025 state brackets effective Jan 1, 2025 (Tax Foundation 2025 dataset).
Income after your state's deductions and exemptions — entering gross income will overstate your tax
Your Connecticut Tax Estimate
State Tax
$3,375
Effective Rate
4.50%
Marginal Rate
5.50%
Tax Bracket Breakdown
Connecticut Tax Facts
Connecticut's progressive tax system has a top rate of 6.99%.
- Tax System: Progressive Brackets
- Connecticut uses a personal exemption ($15,000 single / $24,000 MFJ for 2025) that phases out at higher AGI; no standard deduction.
- Lowest two rates cut to 2% and 4.5% effective TY 2024 and later (CT PA 23-204). Top rate 6.99% on income > $500K (single) / $1M (MFJ). Source: CT DRS Form CT-1040 TCS (Rev. 12/25).
Compare With Other States
Neighboring States
Common take-home amounts in Connecticut
Connecticut 2025 Tax Brackets
Connecticut uses graduated brackets — each slice of income is taxed at the rate shown below. Only the income inside a bracket is taxed at that rate.
Single
| Taxable income | Tax rate |
|---|---|
| $0 – $10,000 | 2.00% |
| $10,000 – $50,000 | 4.50% |
| $50,000 – $100,000 | 5.50% |
| $100,000 – $200,000 | 6.00% |
| $200,000 – $250,000 | 6.50% |
| $250,000 – $500,000 | 6.90% |
| Over $500,000 | 6.99% |
Married Filing Jointly
| Taxable income | Tax rate |
|---|---|
| $0 – $20,000 | 2.00% |
| $20,000 – $100,000 | 4.50% |
| $100,000 – $200,000 | 5.50% |
| $200,000 – $400,000 | 6.00% |
| $400,000 – $500,000 | 6.50% |
| $500,000 – $1,000,000 | 6.90% |
| Over $1,000,000 | 6.99% |
Head of Household
| Taxable income | Tax rate |
|---|---|
| $0 – $16,000 | 2.00% |
| $16,000 – $80,000 | 4.50% |
| $80,000 – $160,000 | 5.50% |
| $160,000 – $320,000 | 6.00% |
| $320,000 – $400,000 | 6.50% |
| $400,000 – $800,000 | 6.90% |
| Over $800,000 | 6.99% |
Each rate applies to taxable income over the lower figure, up to and including the upper figure, which is how this calculator figures the tax.
How Connecticut compares to neighboring states
Bracket and deduction figures are checked against the state revenue department and the Tax Foundation database, with a documented correction ledger. The calculator applies brackets to the state taxable income you enter; deductions and exemptions are shown for reference, not auto-applied. Connecticut rate data was last reviewed for the 2025 tax year; 2026 figures are updated as states publish them.
Disclaimer: This calculator provides estimates for educational purposes only. Not tax, legal, or financial advice. Consult a qualified CPA or tax professional for your specific situation.