What is the average effective property tax rate in Connecticut?

Connecticut's average effective property tax rate is approximately 1.79% of fair market value as of 2024, according to Tax Foundation and ATTOM data. This makes Connecticut one of the highest property-taxed states in the country, ranking in the top five nationally. The effective rate is the ratio of annual property taxes actually paid to the full market value of the property — it accounts for Connecticut's 70% assessment ratio and the varying mill rates set by each of the 169 municipalities.

How does Connecticut's 70% assessment ratio work?

Under Connecticut General Statutes Section 12-64, every municipality must assess real property at 70% of its estimated fair market value. This figure is called the assessed value or the 'grand list' value. The mill rate is then applied to the assessed value, not the market value. For example, a $400,000 home has an assessed value of $280,000. If the town mill rate is 25.57 mills, the annual tax is $280,000 x 0.02557 = $7,160 — which equals the 1.79% effective rate on the $400,000 market value.

What is a mill rate and how do I use it?

A mill rate is the amount of tax payable per $1,000 of assessed property value. One mill equals $1 per $1,000. To calculate your annual tax manually, divide your assessed value by 1,000 and multiply by the mill rate. Connecticut mill rates range from around 10–15 mills in wealthier Fairfield County towns like Greenwich and Darien to over 70 mills in Hartford. The calculator converts the effective rate you enter into the approximate mill rate equivalent so you can cross-check against your town's published rate.

Which Connecticut county has the highest property tax rate?

Tolland County carries the highest average effective property tax rate in Connecticut at approximately 2.16% of market value, followed closely by Windham County at about 2.10% and Hartford County at about 2.03%. At the lower end, Fairfield County averages around 1.41% — reflecting the high market values in towns like Greenwich, Westport, and Darien, where assessed values are large but mill rates are kept relatively low. Within any county, individual town rates vary significantly; always check your specific municipality's mill rate at portal.ct.gov/OPM or your town assessor's website.

When are Connecticut property taxes due?

Connecticut property taxes are typically billed semi-annually. The first installment covers July 1 through December 31 and is due July 1 (with a grace period through August 1). The second installment covers January 1 through June 30 and is due January 1 of the following year (grace period through February 1). Some municipalities issue a single annual bill for lower-value properties. Interest accrues at 1.5% per month (18% per year) on overdue amounts. If your property is mortgaged, your lender usually collects taxes through an escrow account and pays the town directly.

Can I appeal my Connecticut property tax assessment?

Yes. If you believe your property is over-assessed, you can appeal to your town's Board of Assessment Appeals (BAA) each year. The appeal window opens February 1 and typically runs through February 20. You will need evidence that your property's true market value is lower than the assessor's estimate — comparable recent sales, an independent appraisal, or evidence of physical errors in the assessment record. If the BAA ruling is unsatisfactory, you can appeal further to the Superior Court. Connecticut properties are subject to a full revaluation by the assessor at least every five years; between revaluations, values may be adjusted for additions, permits, or sales.

Connecticut Property Tax Calculator

The Connecticut property tax calculator estimates your annual and monthly property tax bill based on your home’s fair market value and Connecticut’s average effective property tax rate of 1.79% — one of the highest in the United States. Select a county preset to refine the figure, or type any rate to model a specific town’s mill rate. Everything runs in your browser; no data is transmitted.

How the calculation works

Connecticut property tax flows through two steps. First, the assessor applies the statutory 70% assessment ratio (Connecticut General Statutes Section 12-64):

Assessed value = fair market value x 0.70

Second, the municipality applies its mill rate to the assessed value:

Annual tax = assessed value x (mill rate / 1,000)

The “effective rate” this calculator uses collapses both steps into a single percentage of market value, making it easy to compare towns and plan a budget without knowing your town’s exact mill rate. The calculator also shows the mill-rate equivalent for cross-checking.

Connecticut’s average effective property tax rate: 1.79%

Connecticut’s statewide average effective property tax rate is approximately 1.79% of fair market value as of 2024 (Tax Foundation; ATTOM Data Solutions). This places Connecticut among the five highest property-taxed states in the country. The rate reflects the combined effect of Connecticut’s 70% assessment ratio and the wide spread of mill rates across its 169 municipalities — from roughly 10–15 mills in wealthy Fairfield County shore towns to over 70 mills in Hartford and Bridgeport.

County averages vary considerably:

County	Avg. effective rate
Tolland	2.16%
Windham	2.10%
Hartford	2.03%
New London	1.95%
New Haven	1.76%
Middlesex	1.65%
Litchfield	1.57%
Fairfield	1.41%

Even within a county, individual towns differ. Greenwich charges around 10–11 mills while Bridgeport charges over 53 mills. Always confirm your town’s current mill rate at portal.ct.gov/OPM or your assessor’s office.

Worked example

A homeowner in West Hartford (Hartford County, approx. 2.03% effective rate) owns a home with a fair market value of $450,000:

Assessed value: $450,000 x 0.70 = $315,000
Mill rate equivalent: 2.03% effective / 0.70 = ~29 mills
Annual tax: $315,000 x 0.029 = $9,135
Monthly tax: $9,135 / 12 = $761.25

The same $450,000 home in Fairfield County (1.41%) would yield approximately $6,345 per year — a difference of nearly $2,790 per year, or $233 per month.

Market value	Hartford Co. (2.03%)	Fairfield Co. (1.41%)	CT avg (1.79%)
$250,000	$5,075	$3,525	$4,475
$400,000	$8,120	$5,640	$7,160
$600,000	$12,180	$8,460	$10,740
$800,000	$16,240	$11,280	$14,320

Property tax and your mortgage

Mortgage lenders in Connecticut typically require an escrow account that collects one-twelfth of your estimated annual property tax with each monthly payment. The lender then pays the town directly when the bill is due. Use the monthly figure from this calculator to check your escrow estimate — if property values have risen since your last assessment, your escrow payment may need adjusting to avoid a year-end shortfall.

Privacy note

This tool is entirely client-side. Your home value and rate figures are never transmitted to any server, stored in any database, or shared with any third party. You can use it offline once the page has loaded.