CT Mill Rates · Free · No signup Connecticut
Connecticut Property Tax Estimator

Know the full cost
before you build.

Enter your town and project details to instantly estimate your property tax impact — powered by real mill rates for all 169 Connecticut towns.

All 169 CT towns FY 2024–2025 mill rates Additions, new builds, ADUs & renovations Built for homeowners & architects
Step 1 — What are you building?
Step 2 — Location & project details
Addition · Colchester, CT
New home value
Annual taxes (new)
Monthly increase
added to your bill
Current assessed value (70%)
Value added by project
New assessed value
Mill rate ()
Current est. annual taxes
New est. annual taxes
Annual tax increase

Mill rate source: CT Office of Policy and Management · FY 2024–2025 · Assessment ratio: 70% (CT state law)

These estimates use Connecticut's 70% assessment ratio and official FY 2024–2025 mill rates. Actual taxes depend on your assessor's valuation of the completed project, applicable exemptions, and any special district overlays. Construction cost is estimated from regional CT averages if not entered manually. Always verify with your local town assessor before making financial decisions.

Connecticut mill rates — all 169 towns

Every mill rate below is sourced from the CT Office of Policy and Management for FY 2024–2025. You can also view the full official dataset on the Connecticut Open Data portal.

Mill rates shown are for real and personal property. Motor vehicle rates may differ. Assessment ratio: 70% of fair market value per CT state law.

How Builtly estimates your taxes
The formula

Connecticut assesses all property at 70% of market value by state law. Builtly estimates the value your project adds, then applies your town's official mill rate.

Assessed value = home value × 70%
Annual tax = (assessed ÷ 1,000) × mill rate

Mill rates come directly from the CT Office of Policy and Management and are updated each fiscal year.

Example — Hebron, CT
Current home value: $400,000
800 sq ft addition added
Est. value added: ~$136,000
New home value: $536,000
Assessed at 70%: $375,200
Hebron mill rate: 35.67
Current taxes: $9,828/yr
New taxes: $13,381/yr
Tax increase: ~$3,553/yr · $296/mo