What’s the fastest way for you to estimate your total monthly cost to own (mortgage, taxes, insurance, HOA)?
The fastest way to estimate your total monthly cost is to pull four numbers for one specific address and add them up. Three of those numbers are public and take minutes to find, and the fourth is an insurance quote.
National payment calculators often miss in Massachusetts because they guess the escrow pieces, especially property taxes. Here the tax rate is stated in dollars per $1,000 of assessed value, not as a percentage of what you pay.
Why Your Calculator Is Wrong in Massachusetts
Most national calculators get principal and interest right, but the tax line is an address-level number they can’t reliably infer here. Your city or town sets its own residential rate in dollars per $1,000 of assessed value, and neighboring towns can be far apart. For FY2026, Rockport charges $8.46 and Topsfield charges $15.66, per the Massachusetts DOR Tax Rates by Class report. A statewide average can be off by hundreds a month even when your principal and interest figure from a mortgage payment calculator is exactly right.
The rate alone won’t tell you which town is cheaper, either. Marblehead’s FY2026 residential rate of $8.56 runs about 21 percent below Salem’s $10.78. Yet DOR’s FY2026 average single-family tax bill works out to roughly $921 a month in Marblehead against $607 in Salem. That’s $314 more every month in the town with the lower rate, because the assessed values are higher. If you’ve been comparing towns by their tax rate, you’ve been reading the wrong column.
You may also have read that buying a house resets its assessment to whatever you paid. It doesn’t work that way here. Assessments are set as of January 1 from the prior year’s sales across the whole town, so yours will often differ from your purchase price in either direction.
Where to Find the Four Numbers
Accurate inputs for one address beat a smarter calculator every time, and three of the four are public records rather than estimates. Guessing even one can make a payment look fine on paper and feel tight in real life.
- Principal and interest. Run the loan amount and rate through a payment calculator. A national tool already handles that part well.
- The property tax for that address. Start at the town’s assessor page and click through to its online property database, which is the current record. Take the assessed value, divide by 1,000, multiply by the town’s FY2026 residential rate, then divide by 12.
- Homeowners insurance. Get a bindable quote on the real address, since this is the one number nobody can look up for you. Keep it separate from mortgage insurance, which protects the lender rather than your property.
- The condo or HOA fee. Read it off the listing, then confirm it against the condominium documents and the 6(d) certificate, which the association must furnish within ten business days of a written request. Our answer on HOA fees and your mortgage payment covers how those dues behave.
Special assessments get voted separately and stay outside that fee, so ask what’s been assessed or discussed. Water, sewer and trash arrive as separate town bills too.
How to Read the Loan Estimate
Once you’re serious about one house, the shortcut is the Loan Estimate the lender issues. Federal rules require delivery within three business days of your application, and an application is only six items. Those are your name, your income, your Social Security number for a credit report, the property address, an estimate of the property’s value, and the loan amount you want. You don’t even need a signed purchase and sale agreement, as the CFPB spells out.
Read the Projected Payments table carefully, because this is where buyers double their own escrow by accident. The Estimated Total Monthly Payment adds up three lines, which are Principal and Interest, Mortgage Insurance, and Estimated Escrow. The rule that builds the form says so. The separate Estimated Taxes, Insurance and Assessments box overlaps those escrowed items, so adding both boxes counts your escrow twice.
Start with the Estimated Total Monthly Payment, then read the “In escrow?” column beside Estimated Taxes, Insurance and Assessments. Anything marked No is a separate bill on top of that total, and condo and HOA dues are usually marked No. A 0 on the Estimated Escrow line means there’s no escrow account at all, so those bills reach you in big lump sums.
A fixed interest rate fixes only your principal and interest. Your servicer re-analyzes the escrow account every year. And Proposition 2 1/2 limits your community’s total levy, which Boston’s assessing office notes doesn’t cap the growth in individual assessments.