The Boston landlord cash flow calculator below gives you a complete financial picture of any Greater Boston rental property — monthly cash flow, cap rate, cash-on-cash return, a 10-year projection that accounts for rent growth and appreciation, and a full expense breakdown. Enter your actual numbers and get results in seconds.
Property details
Financing
Income
Expenses
Key metrics
10-year cash flow & equity projection
Monthly income & expenses
Expense allocation
How to use this calculator
Enter your purchase price, down payment, interest rate, and loan term in the Financing section. Input your expected gross monthly rent across all units — for a triple-decker generating $1,600/unit, that’s $4,800/month total. Set your vacancy rate (5% is standard for Greater Boston), and fill in annual expenses including property tax, insurance, water/sewer, maintenance, and any management fee.
Click through to Results for your headline metrics, then check the 10-Year Projection tab to see how cash flow and equity evolve as rents grow and the mortgage amortizes. The Expense Breakdown tab shows exactly where every dollar goes each month.
What is a good cap rate in Boston?
Greater Boston cap rates typically range from 3.5% to 5.5% for residential multi-family properties. Premium neighborhoods like South End, Back Bay, and Cambridge compress toward 3.5-4.5%. Value neighborhoods like Dorchester, Quincy, and Malden offer 5-6.5% cap rates with higher management intensity. A cap rate below 3.5% requires strong appreciation conviction to justify. Above 6% in Boston usually signals either distress, a value-add opportunity, or an outer-market location.
The Boston market rewards long-term holders — appreciation of 4-6% annually has historically been the primary return driver, with cash flow providing current income while equity builds. For a comprehensive analysis of Boston’s investment landscape, see our Boston investment properties guide and our Boston cap rate calculation guide.
Boston-specific inputs to get right
Property taxes in Boston proper typically run $8,000-$14,000/year for multi-family properties depending on assessed value and classification. Cambridge has a lower residential tax rate than Boston. Insurance on a triple-decker runs $2,500-$4,000/year. Water and sewer for a 3-unit building averages $1,500-$2,400/year depending on tenant usage. Maintenance at 8-10% of gross rent is appropriate for older Boston housing stock — newer construction can use 5-6%.
For current rental pricing data to calibrate your gross rent input, see our Boston Rental Market Report 2026. Connect with a Homzora partner agent who specializes in investment properties to find opportunities that match your return requirements.
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Partner With UsBoston rental property benchmarks: what the numbers mean
The calculator above gives you your specific numbers — but understanding how those numbers compare to the Greater Boston market requires context. Here’s what experienced Boston investors use as benchmarks in 2026:
Cap rate: 3.5–4.5% is normal for premium Boston neighborhoods (South End, Back Bay, Cambridge). 4.5–5.5% is achievable in mid-tier markets (South Boston, Jamaica Plain, Somerville). 5.5–7% is available in value markets (Dorchester, Quincy, Malden) with higher management intensity. Above 7% typically indicates distress, significant deferred maintenance, or an outer market like Worcester or Springfield. If your calculator shows below 3.5%, you need to negotiate the price down or find ways to increase revenue before acquiring.
Cash-on-cash return: 5–8% is a reasonable target for a stabilized Boston rental property. Negative cash-on-cash is common in premium neighborhoods where appreciation expectations are embedded in the price — many Boston landlords accept -2% to +2% cash-on-cash for properties with strong appreciation trajectories. Above 10% cash-on-cash in Boston almost always means either significant value-add opportunity (renovations needed, below-market rents) or elevated risk.
Monthly cash flow per unit: Positive $100–$300/unit is considered good for Greater Boston at current prices and rates. Break-even to slightly negative is common and acceptable for appreciation plays. Negative $500+/unit requires strong appreciation conviction and financial cushion to sustain.
Boston triple-decker investment: the classic play
The three-family triple-decker is Boston’s signature investment vehicle — and for good reason. A $700,000–$850,000 triple-decker generating $1,500–$1,700/unit/month produces $4,500–$5,100/month in gross rent. With 25% down ($175,000–$212,500), the mortgage at 7% runs approximately $3,700–$4,500/month. After taxes, insurance, water, and maintenance, monthly cash flow typically ranges from break-even to +$200/month in today’s market — not spectacular, but acceptable for a property that appreciates and builds equity simultaneously.
The house-hack variation improves the numbers significantly. An owner-occupant purchasing a triple-decker with FHA financing (3.5% down — as low as $24,500 on a $700,000 property) and living in one unit while renting the other two can reduce effective housing costs to near zero or below. Two units at $1,600/month each cover $3,200 of a $3,700 mortgage payment — meaning the owner-occupant’s effective housing cost is approximately $500/month for a Boston property. For a complete breakdown of Boston investment strategies, see our Boston investment properties guide.
The expenses Boston landlords most often underestimate
Running the calculator with unrealistic expense assumptions produces misleadingly positive results. Here’s what Boston landlords consistently underestimate in their initial analysis:
Maintenance and capital expenditures: Boston’s older housing stock — most triple-deckers were built 1890–1950 — requires more maintenance than the rule-of-thumb 8–10% of gross rent suggests for newer properties. Older properties with aging roofs, plumbing, and electrical systems can experience years of low maintenance followed by $15,000–$30,000 capital expenditure events (roof replacement, boiler replacement, electrical panel upgrade). Build a capital reserve of at least 5% of property value and treat it as a real expense even in years you don’t spend it.
Vacancy during turnover: Boston’s September 1st lease cycle means that units turning over in any month other than September may sit vacant for 4–8 weeks while the landlord waits for the market to absorb them. A 5% vacancy rate assumption implies one month vacant per 20 months — realistic for September turnovers, optimistic for off-cycle turnovers. Model 8–10% vacancy if you anticipate tenant turnover during non-peak periods.
Tenant turnover costs: Each tenant turnover in a Boston apartment typically costs $1,500–$4,000 in cleaning, minor repairs, repainting, and potential landlord-paid broker fee. These costs aren’t captured in the maintenance percentage — they’re one-time turnover events that should be modeled separately or added to your vacancy and maintenance inputs.
Legal and compliance costs: Massachusetts’s tenant-favorable legal environment creates real ongoing compliance costs — attorney review of leases, occasional eviction proceedings (which run $2,000–$5,000+ in Massachusetts), security deposit compliance, and the administrative burden of regulatory compliance. Budget $500–$1,000/year per property for legal and compliance costs even in years with no disputes.
Financing options that change the math
The calculator defaults to conventional investment property financing at 25% down — the standard for non-owner-occupied purchases. But several financing strategies can improve your cash-on-cash return significantly:
FHA owner-occupant (3.5% down): Available for 2–4 unit properties where the buyer lives in one unit. Dramatically reduces the required down payment and improves cash-on-cash return, at the cost of living in the property for at least one year. Try the calculator with 3.5% down to see how the numbers change.
MassHousing: Massachusetts’s public housing finance agency offers competitive rates and down payment assistance for owner-occupants with income up to approximately $169,000 for single borrowers. For eligible buyers, MassHousing financing can improve monthly cash flow by $200–$400 compared to conventional financing. For more on Massachusetts financing programs, see our first-time home buyer guide.
DSCR loans: Non-QM investment loans that qualify based on the property’s rental income rather than personal income. Available at 20–25% down with rates typically 0.5–1% above conventional. Valuable for investors with complex income situations (self-employed, multiple properties) who don’t qualify for conventional financing.
10-year return modeling: why it matters
The 10-Year Projection tab in the calculator above shows something that pure cash flow analysis misses: the compounding effect of rent growth and appreciation over time. A property that barely cash flows today with 3% annual rent growth and 4% annual appreciation can deliver exceptional total returns over a decade. By year 5, the same property that was break-even at acquisition may generate $500–$800/month in positive cash flow as rents have grown while the mortgage payment remains fixed.
This is the fundamental Boston investment thesis: accept compressed initial yields in exchange for the appreciation and income growth that Boston’s structural supply constraints and employment demand anchors have consistently delivered. The 10-year model makes this trajectory visible and helps you evaluate whether the current-day numbers justify the investment given your return objectives and time horizon.
Essential tools for Boston landlords
Once you’ve analyzed the numbers and acquired a property, running it efficiently requires the right systems. These Homzora guides cover the operational side of Boston landlording:
→ Best Landlord Tools 2026 — software, apps, and systems for Boston property managers
→ Best Property Management Software — Buildium, Avail, TurboTenant compared
→ Best Physical Tools Every Landlord Needs — equipment guide to stop overpaying contractors
→ Best Smart Locks for Apartments — remote access, code management, and keyless entry for rental units
→ How to Increase Rental Income on Boston Properties — practical strategies for maximizing returns
→ Boston Rental Market Report 2026 — current rent data to calibrate your gross rent inputs
→ Best Places to Buy Multi-Family Property in Massachusetts — market-by-market comparison from Boston to Worcester
