Massachusetts Tax Guide 2026: Flat Tax, Millionaire Surtax, and Estate Tax

Massachusetts is known as a flat-tax state — a straightforward 5% on most income — but two provisions dramatically complicate the picture for higher earners and wealthier families. The 2022 Millionaire Surtax (officially the ‘Fair Share Amendment’) imposes an additional 4% on income above $1 million, creating a 9% combined top rate. And Massachusetts’s estate tax, with its $2 million threshold and notorious ‘cliff effect,’ means estates just over $2M pay tax on the entire estate — not just the excess — making it one of the most punitive estate tax structures in the country.

This guide covers Massachusetts’s income tax structure (including the Millionaire Surtax), the higher 8.5% rate on short-term capital gains, the estate tax cliff, property taxes under Proposition 2½, the clean 6.25% sales tax, and how Social Security and retirement income are treated.

Massachusetts Income Tax: The Flat 5% and the Millionaire Surtax

The 5% Flat Rate

Massachusetts imposes a flat 5% income tax on most income. The rate was reduced from 5.05% in 2020 and has progressively declined from its historical high of 5.95% (pre-1999) through a series of voter-mandated reductions. The flat rate applies to wages, salaries, business income, long-term capital gains, pension income (with some exceptions), interest, and dividends. Massachusetts uses its own income definition — starting with federal AGI but with significant Massachusetts-specific modifications.

The Fair Share Amendment: 4% Surtax on Income Above $1 Million

In November 2022, Massachusetts voters approved a constitutional amendment — the Fair Share Amendment, colloquially called the ‘Millionaire Tax’ — adding a 4% surtax to income above $1 million, effective January 1, 2023. The mechanics:

• Income up to $1,000,000: taxed at the standard 5%
• Income above $1,000,000: taxed at 9% (5% base + 4% surtax)
• The $1M threshold is per taxpayer, per year — it is not indexed to inflation, meaning more earners will gradually be affected over time
• Applies to all income types that are subject to the 5% rate, including wages, business income, and long-term capital gains above $1M

The surtax revenue is constitutionally dedicated to education and transportation funding. In practice, this makes Massachusetts’s effective top rate one of the highest in the Northeast for high earners, though still below California’s 13.3% top rate or New Jersey’s 10.75%.

Short-Term Capital Gains: 8.5%

Massachusetts taxes short-term capital gains (assets held 12 months or less) at 8.5% — notably higher than the standard 5% flat rate. Long-term capital gains (assets held more than 12 months) are taxed at the standard 5% flat rate. This creates a meaningful incentive to hold investments for at least one year before selling.

Tax Burden Comparison at Key Income Levels

Approximate estimates. Actual taxes depend on deductions, filing status, and specific income sources.

Massachusetts Estate Tax: The $2M Cliff and No Portability

The Estate Tax Threshold and Cliff Effect

Massachusetts imposes a state estate tax on estates valued above $2 million. What makes it particularly unusual is the ‘cliff effect’: if an estate exceeds $2 million by even $1, the entire estate — not just the amount over $2 million — becomes subject to tax. This is in contrast to most estate tax structures where only the amount above the threshold is taxed.

Example: An estate worth $2,000,001 pays Massachusetts estate tax on the full $2,000,001. An estate worth $1,999,999 pays $0. This creates an extreme marginal rate situation just above the $2M threshold and makes estate planning critical for Massachusetts residents with assets approaching this level.

Rates and No Portability

Massachusetts estate tax rates range from 0.8% to 16%, graduated. The $2M threshold is not indexed to inflation (unlike the federal exemption which adjusts annually), meaning it captures an increasing number of estates over time, particularly in high-cost areas like Boston, Cambridge, and the South Shore where home values alone can approach or exceed $2M for longtime owners.

Critically: Massachusetts does not allow portability between spouses. Under federal law, a surviving spouse can inherit the deceased spouse’s unused estate tax exemption. Massachusetts has no such provision. This means married couples must engage in active estate planning — typically through trusts — to utilize both spouses’ $2M exemptions. Without planning, a couple with $4M in assets could potentially have $2M+ subject to Massachusetts estate tax upon the second spouse’s death.

Non-Residents with Massachusetts Real Estate

Massachusetts estate tax applies to Massachusetts-based real estate owned by non-residents. If you live in Florida or Texas but own a vacation home in the Berkshires or Cape Cod worth $2M+, Massachusetts estate tax may apply to that property upon your death. This is an important planning consideration for out-of-state vacation property owners.

Property Tax: Proposition 2½

Massachusetts property taxes average approximately 1.17% effective rate statewide — moderate by Northeast standards. The key constraint is Proposition 2½, a 1980 voter initiative that limits annual property tax levy increases to 2.5% above the prior year’s levy (plus new construction). Communities can exceed this limit with a majority vote at town meeting or local election (called an ‘override’).

• Boston: approximately 0.55% effective (city benefits from commercial tax base shifting burden away from residential)
• Cambridge: approximately 0.57%
• Newton: approximately 1.02%
• Worcester: approximately 1.67%
• Springfield: approximately 1.89%

Retirement Income, Sales Tax, and Living in Massachusetts

Retirement Income Treatment

Massachusetts has a split treatment of retirement income:

• Social Security benefits: Fully exempt from Massachusetts income tax
• Massachusetts state and local government pensions (MTRS, PERAC, CERS): Fully exempt from Massachusetts income tax. This is a significant benefit for Massachusetts teachers, public employees, and municipal workers.
• Federal government pensions: Fully exempt from Massachusetts income tax
• Military retirement pay: Fully exempt from Massachusetts income tax
• Private 401(k), 403(b), IRA distributions: Taxed at the standard 5% flat rate (no exemption for private retirement income)

The distinction between public and private retirement income creates a notable split: a Massachusetts teacher with a $60,000/year pension pays $0 in Massachusetts state income tax on that pension, while a private sector employee taking the same amount from a 401(k) pays $3,000/year. This frequently surprises people relocating from states with full retirement income exemptions.

Sales Tax: Simple and Clean

Massachusetts has a 6.25% flat statewide sales tax with no local additions — a rare simplicity in the US sales tax landscape. The same rate applies in Boston as in the Berkshires. Key exemptions: groceries (unprepared food), prescription drugs, clothing under $175 per item, and newspapers are all exempt. This means the effective sales tax burden on a typical household’s spending is meaningfully lower than the headline 6.25%.

The Millionaire Surtax and Expat Considerations

The 4% Millionaire Surtax affects not just residents — it also applies to Massachusetts-sourced income of non-residents. A New York-based executive with a Massachusetts employer or significant Massachusetts business income above $1M will owe the 4% surtax on the Massachusetts-apportioned income above $1M. For US expats who maintain Massachusetts domicile while living abroad, Massachusetts’s aggressive residency rules mean income may remain taxable in Massachusetts even when living overseas. Expats who have not properly established domicile in another state before moving abroad may continue to owe Massachusetts income tax. Documenting the abandonment of Massachusetts domicile before departure is essential for anyone relocating internationally.