Car Taxes in CT: Valuation, Mill Rates, and Exemptions

Car taxes in Connecticut are billed by your town, not the state, and starting with the October 1, 2024 assessment year every municipality calculates them the same way: your vehicle’s manufacturer’s suggested retail price (MSRP) is run through a statutory depreciation schedule, assessed at 70% of that depreciated value, and multiplied by your town’s motor vehicle mill rate, which is capped at 32.46 mills.¹

How Your Vehicle Is Valued

Assessors no longer use the NADA guide. They start with your vehicle’s original MSRP and apply a depreciation percentage based on how old the vehicle is on October 1.²

Up to 1 year old: 85% of MSRP
2 years: 80%
3 years: 75%
4 years: 70%
5 years: 65%
6 years: 60%
7 years: 55%
8 years: 50%
9 years: 45%
10 years: 40%
11 years: 35%
12 years: 30%
13 years: 25%
14 years: 20%
15 to 19 years: 15%
20 years and older: minimum $500 value

Your town may be using a slightly slower schedule. Under Public Act 25-2, a municipality can vote to adopt a modified table that starts at 90% of MSRP for the first year and drops by roughly five points less at each subsequent step.² Ask your assessor which one applies where you live.

Whatever the depreciated value comes to, only 70% of it is taxable. That 70% ratio is the same in every Connecticut town.¹ A three-year-old car with a $40,000 MSRP depreciates to $30,000 (75%), then gets assessed at $21,000 (70% of $30,000). That $21,000 is the number your tax bill is built on.

One trap: unregistered vehicles are not exempt. As of the 2024 assessment year, a car sitting in your driveway without plates is valued the same way as any registered vehicle.¹

The Mill Rate and What You Actually Owe

A mill is one dollar of tax for every $1,000 of assessed value.³ Towns set their own rates each year at budget time, and you can find yours on the OPM mill rate page or your municipal website.

For motor vehicles, no town can charge more than 32.46 mills, even where the real estate rate runs higher.¹ The math is assessed value times mill rate divided by 1,000.³ The $21,000 assessment above, in a town at the cap, produces a bill of $681.66. In a town at 25 mills, the same car owes $525.

When It’s Due and What Late Costs

Regular motor vehicle bills are due July 1, calculated from the previous October 1 grand list. Payment has to arrive by August 1 to avoid interest, thanks to a grace period of about 30 days.⁴

Bought a car after October 1? You’ll get a supplemental bill instead, prorated for the months left in the assessment year. Supplemental billing schedules vary; some towns bill monthly, others at set intervals.⁵ Call your tax collector if you aren’t sure when yours is coming.

Interest on late payments runs 1.5% per month, or 18% annualized, and it’s backdated to the original due date the moment you miss it.⁵ On a $600 bill, that’s $9 in the first month and it compounds. Most towns take payment online, by mail, or in person; card and e-check payments usually add a processing fee.

If You Sold the Car, Totaled It, or Moved Out of State

You can get a prorated credit so you’re only paying for the months you actually owned and registered the vehicle in that town. The town won’t do this on its own. You have to bring documentation to the assessor, and the key piece is the plate return receipt from the Connecticut DMV.⁶ If you didn’t keep yours, request a duplicate.

The receipt alone won’t do it. You also need proof of what happened to the car:⁷

Sold or donated: bill of sale, trade-in agreement, or title transfer record.
Stolen or totaled: a letter on your insurer’s letterhead giving the VIN, the date the title was taken, and confirmation that the vehicle was a total loss or not recovered.
Moved out of state: a copy of your out-of-state registration or title.

The filing deadline is December 31 following the first full assessment year after the event.⁸ Sell a car in March 2026 and you have until December 31, 2027. Miss it and you owe the full tax on a car you no longer have.

Leaving Connecticut? Cancel your plates through the DMV before you go. If you don’t, the vehicle stays on the town’s grand list and the bills keep coming.⁶

Exemptions

Antique, Rare, and Special Interest Vehicles

Qualifying vehicles are assessed at a flat $500, regardless of market value. The car has to be at least 20 years old, preserved for historical interest, and unmodified from original manufacturer specs. Antique plates aren’t required, but without them the assessor may ask for documentation.⁹

Disabled Veterans

Veterans with a service-connected permanent and total disability rating from the U.S. Department of Veterans Affairs qualify for a property tax exemption. It normally applies to the primary residence, but a veteran who doesn’t own a home can apply it to one motor vehicle instead.¹⁰ You have to live in Connecticut and file with your town assessor.

Appealing Your Assessment

The Board of Assessment Appeals hears motor vehicle appeals in September. Under the MSRP system, the board can only look at whether the right MSRP was used. High mileage, poor condition, and accident damage no longer qualify as grounds for a reduction.¹¹

MSRP errors do happen, especially on vehicles with unusual trims or factory options. If you think the assessor picked the wrong MSRP for your specific configuration, an appeal is worth filing. Watch your assessor’s website in mid-August; the filing window is short.

Registration Holds for Unpaid Taxes

If a town or city reports you as delinquent, the DMV will deny any registration renewal or new plate transaction until you clear the debt. Paper tax releases are no longer accepted; your tax collector clears the hold electronically, and it can take a day or two to appear in DMV systems.¹² Pay well before your registration expires if you don’t want to get stranded at the DMV counter.

Deducting Vehicle Tax on Your Federal Return

Connecticut’s motor vehicle property tax counts as a deductible state and local tax on your federal return if you itemize. For 2025, the SALT deduction cap is $40,000 for most filers and $20,000 for married filing separately.¹³ The cap phases down above $500,000 in modified adjusted gross income but doesn’t go below $10,000. The 2026 cap is expected to see a small inflation adjustment. That one limit covers all your state and local taxes combined, so your vehicle tax shares space with your Connecticut income tax and any real estate tax you pay.

1
Connecticut General Assembly. Connecticut General Assembly Office of Legislative Research – Personal Motor Vehicle Property Tax Assessments and Rates
2
State of Connecticut Office of Policy and Management. Motor Vehicle Assessment Changes Effective October 1, 2024
3
State of Connecticut Office of Policy and Management. Mill Rates
4
Town of Wilton. Tax Due Dates
5
Bristol, CT – Official Website. Payment Dates
6
Connecticut Department of Motor Vehicles. Cancel Your Registration and Plates
7
City of Norwalk. Office of the Assessor – Motor Vehicle Adjustment Requirements
8
Connecticut General Assembly. An Act Concerning Motor Vehicle Assessments for Property Taxation
9
Connecticut General Assembly. Assessment Limit on Antique Vehicles
10
State of Connecticut. Governor Lamont Signs Law Establishing Property Tax Exemption for Veterans
11
Town of Glastonbury. Assessment Appeal Information
12
Connecticut Department of Motor Vehicles. Learn How to Comply with Insurance, Tax, and Registration Laws
13
Internal Revenue Service. How to Update Withholding to Account for Tax Law Changes for 2025