Buying vs. Renting in Boston: The $2,875 Gap Nobody Is Discussing

The inversion, in one number

A growing family needs a third bedroom. They do what everyone does: they open a search portal, look at what it costs to buy, look at what it costs to rent, and try to work out which one is the responsible decision.

In Greater Boston in September 2026, that comparison is not close. And almost nobody in my industry is saying so out loud.

Take a 1,000 square foot, 3-bedroom condo in Boston at $1,000,000 — a fair number in the core of the city, where Beacon Hill, Back Bay and the Seaport all clear $1,000 per square foot. Put 20% down, which is the responsible version of this story, because anything less adds mortgage insurance and makes the gap worse. Finance $800,000 at the Freddie Mac average of 6.95% as of September 17, 2026.

Owning that unit runs $6,541 a month once you add property tax, insurance and a condo fee to the loan. Renting the same thing runs $3,666. The gap is $2,875 a month — $34,501 a year.

That is not a rounding error or a bad month. That is thirty-four thousand dollars a year to hold the same square footage you could rent. And it is the version that is generous to buying — I have already applied Boston's residential exemption in full.

The assumptions, stated plainly

Anyone can produce a scary number by hiding the inputs. Here are mine, so you can disagree with them specifically.

Two of those are estimates rather than measurements, and I want to be honest about which: insurance and the condo fee. A $500 condo fee on a 1,000 square foot unit is reasonable in much of Boston, but I have seen $250 and I have seen $1,100. Swap in the real number for the building you are actually looking at. Everything else is sourced.

The monthly carry, line by line

And that still excludes utilities you were not paying before, maintenance, and capital expenditure. The renter calls someone when the heat fails. The owner buys the boiler. A special assessment for a roof or a facade does not care what your budget looked like at closing.

What about Boston's residential exemption?

If you know the Boston market, this is the first thing you will push back on — and you should. The residential exemption is the single most valuable break an owner-occupant can claim here, and most buyers never budget for it.

Per the City of Boston Assessing Department, the exemption saved qualifying owner-occupants up to $4,353.74 on their most recent tax bill. That is about $363 a month, and it is real money.

I applied it in full above. The gap is still $2,875 a month. Without it, the number is $3,238. The exemption is worth claiming — you must own and occupy the home and file with Assessing by the deadline — but it does not change the shape of the problem. It also does not exist for investors, which matters if you are running this math on a rental.

One more thing these numbers leave out, and I want to name it rather than have you find it: the mortgage-interest deduction — a family that itemizes can deduct most of the interest on this loan and the property tax on top of it. Depending on your bracket, that is worth several hundred dollars a month in the early years — and it shrinks every year, because the interest share of each payment falls as the loan amortizes. It narrows the gap. It does not close it. Run it with your CPA against your own return, not against mine.

Where the buy vs. rent gap is worst

The inversion is not uniform, and this is the part I have not seen anyone publish. Using average condo price per square foot from my own MLS PIN Area Market Review pulls dated September 15, 2026, each town's FY2026 residential tax rate, and the same $575 a month of insurance and condo fee as the headline case, here is what the same 1,000 square foot, 3-bedroom unit costs to carry. (The headline case above is core Boston at $1,000 per square foot; the Boston row here is South Boston specifically, at the MLS average.)

Loan, property tax, $75 insurance and $500 condo fee — utilities and maintenance still excluded. Every row is compared against the same $3,666 Boston rent; rents in the outer towns run lower, which would widen those gaps. Boston shown with the residential exemption applied; Cambridge, Somerville and Watertown also offer owner-occupant exemptions not modeled here, which would narrow theirs.

Read that column on the right again. The gap runs from $2,500 a month in Cambridge down to about $300 in Watertown, with Newton in between at roughly $600. Nowhere on this list does owning come out cheaper than a Boston rent — but the size of the penalty is not remotely the same from town to town.

That is the useful finding. “Buying is expensive” is a headline. “Buying costs $2,500 a month extra in Cambridge and $300 extra in Watertown” is a decision. If you are set on owning, the outer towns are where the math gets close — they are just further out than most families start looking. Our neighborhood market guides break down each of these markets in detail.

The amortization trap: 82% interest

Here is where the argument usually goes: fine, it costs more — but you are building equity, and rent is throwing money away.

Look at what the first decade of an $800,000 loan at 6.95% actually does.

Ten years of payments — $635,470 of real money — and the loan has moved from $800,000 to $685,689. Eighty-two cents of every dollar went to interest. In year one it is worse: $55,342 of interest against $8,205 of principal.

“Building equity” in the first decade of a high-rate mortgage is mostly a story we tell ourselves. The equity is real, but it is thin, and it is dwarfed by what you paid to get it. In a softening sales market — and much of Greater Boston is softening, which I covered in the 2026 Boston market analysis — the appreciation that was supposed to do the heavy lifting is not showing up either.

What the house has to do just to tie

Here is the fair version of the comparison, and the setup matters more than the chart, so let me be explicit about it.

Two families. Same home, same ten years. The buyer puts $200,000 down, pays about $25,000 in closing costs, and carries $6,541 a month. The renter pays $3,666 a month, then takes the $225,000 they did not put down plus the $2,875 they save every month and puts all of it in a savings account — Marcus by Goldman Sachs pays 3.40% APY as of September 2026. Not stocks. A savings account.

Both families spend exactly the same amount of money over the ten years. That is the whole point of setting it up this way. The only question left is what each one is holding at the end.

The renter is easy to answer: $723,454 in cash. That number does not move, because a savings account does not care what the housing market does.

The owner's answer depends entirely on appreciation — on what the home sells for minus what is still owed and minus the cost of selling. So the honest way to show it is to put the owner's outcome at a range of appreciation rates against that flat $723,454 line:

At flat prices the renter finishes $459,144 ahead. And the savings account carries no roof, no special assessment, no vacancy, no transfer tax, and no five percent to get out.

Broker's Take

What I am not saying

Am I saying nobody should own a home? No. It could not be further from the truth. Home ownership is a fundamental pillar of the American dream, and I have spent my career helping people get there.

There are excellent reasons to buy that never appear in a spreadsheet. Security of tenure — nobody raises your rent or declines to renew. Control over the place you live. School stability for kids. A fixed payment while rents climb. Forced savings for people who will not otherwise save. A decades-long horizon, which changes this math entirely, because the amortization curve that is brutal in year three is generous in year twenty-two.

What I am saying is that the gap is $34,500 a year right now in Boston, and you deserve to be told that before you sign, not after. If you buy anyway, with your eyes open, for reasons that matter to your family — that is a good decision. If you buy because someone told you renting is throwing money away and never showed you the arithmetic, that is not a decision. That is a sales pitch.

For a longer walk through either path, our Buyer's Guide and Renter's Guide cover the mechanics, and the Investor's Guide goes deeper on cash-on-cash underwriting.

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