Connecticut Quarterly Tax Calculator
Calculate your estimated quarterly tax payments for federal and Connecticut state taxes. Designed for self-employed individuals, freelancers, and independent contractors.
CT State Tax: Progressive 2.0% - 7.0%
Quarterly Payment Amount
$6,428
Per quarter (4 remaining)
Annual Tax Breakdown
2026 Payment Schedule
Jan 1 - Mar 31
Due: April 15, 2026
$6,428
Apr 1 - May 31
Due: June 15, 2026
$6,428
Jun 1 - Aug 31
Due: September 15, 2026
$6,428
Sep 1 - Dec 31
Due: January 15, 2027
$6,428
Don't miss your quarterly payments!
The IRS may charge penalties and interest if you underpay or pay late. Consider setting up automatic payments or calendar reminders.
Connecticut Quarterly Tax Highlights
Connecticut has 7 tax brackets with rates from 2% to 6.99%
Additional tax recapture for high earners
Use Form CT-1040ES for quarterly payments
Complex bracket system with multiple rates
Connecticut Quarterly Tax FAQ
What is Connecticut's income tax rate?
Connecticut has a progressive income tax with 7 brackets ranging from 2% to 6.99%. The top rate applies to income over $500,000 (single) or $1,000,000 (married).
Connecticut Estimated Quarterly Tax Payments for Self-Employed Workers in 2026
Self-employed workers in Connecticut must pay both federal estimated taxes to the IRS and state estimated taxes to the Connecticut Department of Revenue Services. Connecticut has a progressive income tax with 7 brackets and rates ranging from 2% to 6.99%. If you expect to owe $1,000 or more in Connecticut state income tax after withholding and credits, you must make quarterly estimated payments using Form CT-1040ES.
Connecticut applies a tax recapture provision for high earners. If your Connecticut AGI exceeds certain thresholds, a percentage of the tax benefit from lower brackets is recaptured, effectively increasing your marginal rate.
| Tax Layer | Rate / Range | Filed With | Form |
|---|---|---|---|
| Federal income tax | 10% – 37% | IRS | 1040-ES |
| Self-employment tax | 15.3% | IRS | 1040-ES / SE |
| Connecticut state income tax | 2% to 6.99% | Connecticut Department of Revenue Services | Form CT-1040ES |
How Connecticut Income Tax Affects Your Quarterly Payments
Connecticut taxes personal income — including self-employment income — across 7 progressive brackets. The brackets below apply to single filers for tax year 2026. Married filing jointly thresholds are typically higher.
| Bracket | Taxable Income (Single) | Marginal Rate |
|---|---|---|
| 1 | $0 – $10,000 | 2.0% |
| 2 | $10,000 – $50,000 | 4.5% |
| 3 | $50,000 – $100,000 | 5.5% |
| 4 | $100,000 – $200,000 | 6.0% |
| 5 | $200,000 – $250,000 | 6.5% |
| 6 | $250,000 – $500,000 | 6.9% |
| 7 | $500,000+ | 6.99% |
To estimate your Connecticut quarterly payment, calculate your projected state tax liability using the brackets above, then divide by four. Connecticut payments are made to the Connecticut Department of Revenue Services through their online portal at portal.ct.gov/DRS or by mail using Form CT-1040ES.
Federal Self-Employment Tax and Quarterly Due Dates
All self-employed workers must pay federal self-employment (SE) tax of 15.3% on 92.35% of net earnings. This consists of 12.4% for Social Security (on earnings up to $184,500 in 2026) and 2.9% for Medicare (no cap). An additional 0.9% Medicare surtax applies to earnings above $200,000 (single filers).
Both Connecticut and federal estimated tax payments follow the same quarterly schedule:
| Quarter | Income Period | Due Date |
|---|---|---|
| Q1 | January 1 – March 31 | April 15, 2026 |
| Q2 | April 1 – May 31 | June 15, 2026 |
| Q3 | June 1 – August 31 | September 15, 2026 |
| Q4 | September 1 – December 31 | January 15, 2027 |
To avoid underpayment penalties, pay at least 100% of your prior-year tax liability (or 110% if your AGI exceeds $150,000) spread across four equal payments, or at least 90% of your current-year tax. You can deduct 50% of your self-employment tax from your adjusted gross income, reducing both your federal and Connecticut taxable income.
Related Calculators
Official References
This calculator uses current federal and Connecticut tax rates and schedules:
- IRS Estimated Tax Guidelines
Federal quarterly tax requirements and Form 1040-ES
- Connecticut Department of Revenue Services
Official Connecticut tax authority
- IRS Self-Employment Tax
Social Security and Medicare tax information
This calculator provides estimates based on 2026 tax rates. Your actual tax liability may vary based on deductions, credits, and other factors. Consult a tax professional for personalized advice.