Connecticut vs. Massachusetts Taxes: What Actually Changes When You Move

Kevin Hoang was born and raised in Connecticut and lived in South Windsor for 25 years before moving up to Greater Boston, so he has paid both states' bills. The short version: Massachusetts property tax rates look far lower than Connecticut's, and they are, but the houses cost more, so the bills come out closer than the rates suggest. Income tax is simpler here and for most households a little lower. The estate tax is the one that runs hard the other way.

Property tax: why the rates mislead

Connecticut and Massachusetts quote property tax in what look like the same units. They are not the same.

Connecticut sets a mill rate, in dollars per $1,000, and charges it on the assessed value, which state law fixes at 70% of market value (C.G.S. § 12-62a).
Massachusetts sets a rate per $1,000 and charges it on full assessed value, which is meant to be 100% of market value.

So a Connecticut mill rate has to be scaled down by 30% before you compare it with anything here. South Windsor's rate on the October 1, 2025 grand list is 37.01 mills, which is about 2.6% of a house's market value every year. Newton's residential rate for fiscal 2026 is $9.69 per $1,000, under 1%.

That is the rate. The bill is the rate times the house, and the houses are not the same price:

A typical South Windsor home, about $440,000 on Zillow's September 2026 index, pays about $11,400 a year.
A typical Newton home, about $1.48 million, pays about $14,400.
A $500,000 house in South Windsor pays about $12,950, the same bill as a Newton house worth about $1.34 million.

All of that is before exemptions, and many Massachusetts towns add a small Community Preservation Act surcharge on top of the rate. The rule that survives all of it: compare bills, not rates. Ask for the actual tax bill on any house you look at, and for a town you are weighing, multiply its current residential rate by what you would really pay for a house there. How Massachusetts property tax works covers assessments, Proposition 2½ and abatements.

Car tax: a different system entirely

In Connecticut your car is taxed as property by the town where it is garaged: 70% of its value times the town's motor vehicle mill rate, which state law now caps at 32.46 mills (C.G.S. § 12-71e).

Massachusetts charges a motor vehicle excise instead, at a flat $25 per $1,000 (M.G.L. c. 60A, § 1). It is not charged on what the car is worth but on a fixed share of the manufacturer's list price: 90% in the year it was made, then 60%, 40% and 25%, and 10% from the fifth year on. An older car pays very little; a new one pays the most it ever will.

Two things catch people coming from Connecticut:

The first Massachusetts excise bill comes from your new town some months after you register, usually when you have forgotten it is coming.
Your Connecticut town will keep billing you for a car that has left unless you show it otherwise. Before you go, ask the assessor what they need, which is usually proof that the Connecticut registration was canceled and the plates returned.

Income tax

Massachusetts: 5% on most income, plus a 4% surtax on income over $1,107,750 in 2026 ($1,083,150 in 2025). Short-term capital gains are taxed at 8.5%.
Connecticut: graduated, from 2% on the first slice of income to 6.99% at the top (2025 rates).

For most households Massachusetts comes out a little lower, but the difference depends on income and deductions and is worth running rather than guessing.

The year you move

For the year of the move you are a part-year resident of both states. Each taxes what you earned while you lived there, and each can tax income from sources inside it whichever state you live in. You file Form 1-NR/PY in Massachusetts and Form CT-1040NR/PY in Connecticut the following spring. If you sell your Connecticut house the same year, talk to a preparer before the closing rather than after.

Retirement income

Social Security: Massachusetts does not tax it at all. Connecticut exempts it fully when your income is under $75,000 ($100,000 on a joint return), and above that taxes up to 25% of it.
Pensions and IRA withdrawals: each state treats them differently, and the answer depends on where the pension comes from. A government pension in particular is worth checking against both states' rules before you move.

Estate tax: where Massachusetts is harder

Massachusetts: estates under $2 million owe nothing; larger estates are taxed at rates from 0.8% to 16%.
Connecticut: the exemption is $15 million in 2026, with 12% above it.

Two million dollars is not an unusual estate in Greater Boston once a house is counted. A retired couple who own a $1.4 million house outright and have savings can be over the line without ever thinking of themselves as wealthy. If that could be you, see an estate attorney before the move, not after it.

Sales tax

6.25% in Massachusetts and 6.35% in Connecticut, close enough not to matter for most decisions.

The tax when you sell

Connecticut conveyance tax, paid by the seller, in two parts. The state's is 0.75% of the price up to $800,000, 1.25% of the part between $800,000 and $2.5 million, and 2.25% above that (C.G.S. § 12-494). The town adds a smaller share. On a $440,000 sale the state's part is $3,300.
Massachusetts deed excise, customarily the seller's, when you sell here later: $2.28 per $500 of the price, or about 0.46%.

Connecticut exempts from its conveyance tax the first sale of a principal residence whose concrete foundation has deteriorated from pyrrhotite, with a licensed engineer's written evaluation (C.G.S. § 12-498). Selling a Connecticut house to buy in Massachusetts has more on that.

Health insurance: not a tax, but it is on the return

Massachusetts has required adults to carry health insurance that meets state standards since 2006, and you show it on Schedule HC with your state return. Going without can cost a penalty. Connecticut has no such requirement, so if your coverage will not come through an employer, sort it out in your first weeks here.

What it adds up to

Lower rates on more expensive houses, a simpler income tax, no tax on Social Security, and an estate tax that starts far lower. The comparison that matters is your own: the two specific towns, the house you would actually buy, your income and your estate. Kevin can put the housing half of that together with you, and the Connecticut-to-Massachusetts guide has the rest of the move. For the tax half, use a preparer who files in both states.

Rates and thresholds as published by the Massachusetts Department of Revenue and the Connecticut Department of Revenue Services for 2025 and 2026; South Windsor's rate from Connecticut OPM and Newton's from the City of Newton; statutes as published in 2026. All of them change. General information, not tax advice.