1099 Quarterly Taxes in Connecticut (2025-2026)
If you're self-employed in Connecticut — freelancer, contractor, gig worker, or single-member LLC — you owe quarterly estimated taxes to two agencies: the IRS (federal) and Connecticut Department of Revenue Services (state). Connecticut's top marginal rate is 6.99%, applied progressively. Getting your estimates right matters because under-payment penalties stack on top of the actual tax owed.
Connecticut state income tax (2025)
Connecticut uses a progressive bracket system on top of federal tax. For single filers in 2025:
| Income (single filer) | Marginal 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% |
| $500,000+ | 6.99% |
How to pay Connecticut estimated taxes
Federal estimated tax due dates (April 15, June 16, September 15, 2026, and January 15, 2027) apply to your Connecticut state estimated payments as well — most states piggyback on the federal schedule. Pay Connecticut taxes through the Connecticut Department of Revenue Services's online portal: portal.ct.gov/DRS/myconneCT. You can also mail Form CT-1040ES with a check.
Connecticut-specific quirk freelancers miss
Connecticut applies a phase-out 'recapture' for high earners that effectively raises the marginal rate at certain income thresholds. Single filers above $200,000 should plan for the recapture in addition to the marginal rate.
Common deductions for Connecticut freelancers
- Connecticut allows the same business expenses (home office, mileage, software, etc.) as federal.
- Half of SE tax is deductible federally; check Connecticut's rules for state conformity.
- CT does not allow the QBI deduction. Half-SE-tax deduction allowed federally only.
- SEP-IRA / Solo 401(k) contributions reduce both federal and Connecticut taxable income.
- Self-employed health insurance premiums are deductible federally.