5 Numbers That Tell You If a Rental Is Worth Buying

Updated June 21, 2026

The 1% rule used to be the only number a landlord needed. At today's mortgage rates, it puts sixty-nine dollars a month in your pocket — and one broken water heater takes you negative for the year. Here are the five numbers that actually tell you if a rental property is worth buying in 2026.

Key Takeaways

• The 1% rule no longer cash-flows at today's mortgage rates — investment loans of 7.0%–7.5% mean you now need a rent-to-price ratio of 1.1%–1.2% to deliver the cash flow that 1% used to. - Average multifamily cap rates of ~5.0% sit 200+ basis points below current mortgage rates, putting most buyers in a negative leverage position from day one. - A "good" cash-on-cash return in 2026 is 8%–12%; anything under 6% rarely justifies the operational risk and illiquidity of owning property. - Debt service coverage ratio (DSCR) of 1.25 or higher unlocks the best lender pricing — below 1.00 and the property doesn't even cover its own mortgage. - Rents are flat-to-down — the national median is off 1.7% year-over-year (Apartment List National Rent Report) — and Q1 2026 rental vacancy hit 7.3% (Census HVS). Your pro forma needs to assume both, not last cycle's 4% vacancy and 5% rent growth.

Why the 1% Rule No Longer Holds

For decades, landlords screened deals with a single arithmetic gut-check: if monthly rent equaled at least 1% of the purchase price, the deal probably cash-flowed. A $200,000 house renting for $2,000? Worth a closer look. Below that? Pass.

Recommended reading: Liquidity

That heuristic worked because mortgage rates were forgiving. With cheap debt and modest expense loads, 1% covered principal, interest, taxes, insurance, vacancy, and a thin margin of profit. The math always depended on the cost of money, and the cost of money has roughly tripled since 2021.

Investment property mortgage rates ran between 7.0% and 7.5% in early 2026 — roughly 50 to 100 basis points (half a percent to a full percent) above the 30-year fixed for a primary residence, which sat near 6.5%, according to Freddie Mac's Primary Mortgage Market Survey. At those rates, a property hitting exactly 1% — say a $250,000 single-family home renting for $2,500 — generates only about $69 a month in cash flow when self-managed, down from $376 at 4.5% rates. Add a property manager at 8%–10%, one $1,200 turnover, or a single HVAC repair, and the year goes negative.

So professional investors moved the goalpost. The functional 2026 threshold is closer to 1.1%–1.2% rent-to-price with professional management, or roughly 0.8%–1.0% if you self-manage and accept thinner cash flow. On that same $250,000 house, you'd want $2,750–$3,000 in monthly rent before the deal earns its place in your portfolio.

The position is straightforward: 1% is no longer a buy signal. At 2026 rates, a property hitting 1% on the nose stops cash-flowing the moment one repair lands. Treat 1.1%–1.2% as the floor for any cash-flow-driven purchase, and only accept 1% in markets where you have a defensible thesis on rent growth or appreciation, plus a long-term plan to refinance into cheaper debt.

Cap Rates vs. Mortgage Rates: The Negative Leverage Trap

Capitalization rate (cap rate) — net operating income divided by purchase price — is the most-cited screen in real estate. National multifamily cap rates landed around 5.0%–5.1% across the top 30 markets in early 2026, with primary markets like New York, Los Angeles, and Boston compressing tighter, between 4.5% and 5.5%, and secondary and tertiary markets running 6%–9%, based on CBRE's North America Cap Rate Survey.

Now stack that against your borrowing cost. Your mortgage rate is 7.0%–7.5%. The property's unlevered yield is 5.0%. The 200+ basis point gap has a name in commercial real estate: negative leverage. You're paying more for the borrowed half of your capital than the property earns on it, so every dollar of debt makes your return worse, not better.

In a positive-leverage environment, debt amplifies returns. A property earning 8% with a bank charging 5% adds 3% to your return on every borrowed dollar. In a negative-leverage environment, debt erodes returns. A property earning 5% with a bank charging 7.25% costs you 2.25% on every borrowed dollar. The more you finance, the worse you do.

That doesn't make every deal a pass. It means cap rate alone is no longer enough — you need to compare it against three things at once:

Three numbers tell the whole story right now. Your borrowing cost is roughly 7.25 percent. The risk-free 10-year Treasury sits near 4.3. And the average multifamily cap rate is 5.0 — meaning a typical property earns five cents on every dollar of value, while you're paying seven and a quarter cents on every dollar you borrow. That gap is what professional investors call negative leverage. The only places it disappears are the secondary and tertiary markets, where cap rates still run six to nine percent.

If the cap rate is below your mortgage rate, the spread has to be made up somewhere — through forced appreciation (renovations that lift rents), market rent growth, or value-add management. If you're a passive buy-and-hold investor without a clear value-add plan, secondary and tertiary markets at 6%–9% are where the math still pencils out.

Cash-on-Cash Returns: The 8%–12% Lifeline

Cap rate ignores financing. Cash-on-cash return doesn't — it answers the only question that matters once you've signed the loan documents: how much cash does this property put in your pocket each year, divided by how much cash you put in?

The formula is simple: annual pre-tax cash flow ÷ total cash invested. If you put $60,000 down on a $300,000 property and the property nets $5,400 a year after every expense including the mortgage, your cash-on-cash return is 9%. The 2026 industry benchmark for a "good" buy-and-hold rental is 8%–12%. Anything below 6% rarely justifies the illiquidity, tenant risk, and management overhead of owning property — you can earn around 4.3% on a 10-year Treasury with zero hassle, per FRED, and that's the floor any rental has to clear before the work even makes sense. Anything above 15% should be triple-checked: it usually means undisclosed CapEx, deferred maintenance, or risk that hasn't shown up in the pro forma yet.

The worked example below uses the 50% rule as its expense backbone — the long-running landlord rule of thumb that operating costs (taxes, insurance, maintenance, repairs, vacancy, utilities, management) typically eat about half of gross rent before mortgage payments. We'll use a slightly tighter 45% to reflect a self-managed property in a moderate-tax state. Picture a three-hundred-thousand-dollar single-family rental in a secondary market, renting for thirty-three hundred a month — that's the 1.1 percent threshold. You put seventy-five thousand down, plus another nine in closing costs and reserves: eighty-four thousand of your own cash on the line. After vacancy at the current 7.3 percent national rate, after operating expenses eating about 45 percent of gross rent, and after a fifteen-hundred-and-thirty-five-dollar monthly mortgage payment, the property nets you four hundred and sixty-nine dollars for the year. On eighty-four thousand of cash, that's a 0.6 percent return. You'd do six times better leaving it in a Treasury.

That's why 1% deals don't cash flow anymore. Run the same property at $3,600/month rent (1.2%):

• Annual rent: $43,200
• Vacancy: -$3,154
• Operating expenses: -$19,440
• Mortgage P&I: -$18,420
• Annual cash flow: $2,186
• Cash-on-cash return: 2.6%

Still below benchmark. To hit 8% cash-on-cash with these inputs, you need either rent closer to $4,200/month, a bigger down payment that shrinks the mortgage, or a market with materially lower property taxes — effective property tax rates vary roughly eightfold across states, from 0.27% in Hawaii to 2.23% in New Jersey, per the Tax Foundation's Facts & Figures report. Jurisdiction is one of the largest single drivers of cash flow.

Gross Rent Multipliers: Is Your Price Aligned With Rents?

Gross rent multiplier (GRM) is the back-of-envelope test you run before the spreadsheet. Formula: purchase price ÷ annual gross rent. A $300,000 property renting for $3,000/month ($36,000/year) has a GRM of 8.3. A favorable GRM is generally 6–9 for single-family and small multifamily in most U.S. markets, with primary-coastal cities running higher (10–14) and tertiary markets often pricing at 5–7, according to JPMorgan's commercial term lending guidance.

The 8.3 GRM in our cash-on-cash example sits inside that "favorable" range — meaning price and rent are reasonably aligned. It still doesn't cash-flow at 7.25% mortgage rates, which is the point: a favorable GRM is necessary but not sufficient. Financing costs can erase a perfectly priced property's returns regardless of the multiplier.

GRM is most useful as a sanity check between similar properties in the same market. Two duplexes on the same street, both 3-bed/2-bath, both renting for $1,800 a side: if one is listed at $480,000 (GRM of 11.1) and the other at $360,000 (GRM of 8.3), the second one is the conversation-starter. The cheap one might be cheap for a reason — but at minimum, you've found a price anomaly worth investigating.

GRM has a fatal flaw: it ignores expenses, vacancy, and financing entirely. A property with sky-high property taxes, an active homeowners association (HOA), or a roof on its last legs can show a beautiful GRM and a brutal cash flow. National rent data shows just how much variance you're working with: Apartment List's national median was $1,370 in April 2026 — down 1.7% year-over-year, per the Apartment List National Rent Report. The "right" rent for a property depends entirely on the local comp set, not on any national figure.

Use GRM the way professionals do: as a 30-second filter to decide whether a listing deserves a real underwriting model. If the GRM is 12 or 15 in a non-coastal market, you can usually walk. If it's 5 or 6 in a market where the median is 9, you've found something — go figure out why.

Debt Service Coverage Ratio: The Financeability Test

Debt service coverage ratio (DSCR) is the metric your lender cares about most, and it should be the metric you build every pro forma against. Formula: net operating income ÷ annual debt service. A property generating $25,000 in NOI against $20,000 in mortgage payments has a DSCR of 1.25.

Most investment-property lenders set their floor at 1.00 minimum, 1.20–1.25 for standard pricing, and 1.30+ for the sharpest rates. Below 1.00 means the property doesn't generate enough income to cover its own mortgage — you'd be feeding it cash every month. At 1.00 to 1.20, expect a higher rate, a lower loan-to-value cap, or both. At 1.25 and above, you're in the lender's strike zone for non-recourse DSCR loan products and the rate sheet's best column.

Run our $300,000 secondary-market example at the 1.1% rent ratio:

• Gross rent: $39,600
• Vacancy at 7.3%: -$2,891
• Operating expenses at 45%: -$17,820
• Net operating income: $18,889
• Annual debt service: $18,420
• DSCR: 1.025

That property is technically financeable, but barely. One bad turnover or a 50-basis-point property tax reassessment flips it under 1.00. Now run it at the 1.2% rent ratio ($3,600/month):

• Gross rent: $43,200
• Vacancy: -$3,154
• Operating expenses at 45%: -$19,440
• Net operating income: $20,606
• Annual debt service: $18,420
• DSCR: 1.12

Better, but still short of the 1.25 threshold lenders want for the best pricing. To get there, you need either rent above $3,800/month at this purchase price, a larger down payment that shrinks debt service, or a property in a lower-tax jurisdiction where the 45% expense ratio drops to 35%–40%.

DSCR is also where the math meets the loan officer. If your DSCR comes in under 1.00 on paper, you can bring more cash to closing (lowering debt service), negotiate a lower price (raising NOI per dollar borrowed), or walk. Almost no lender will stretch coverage below 1.00 on a true investment property in 2026, and the ones that will charge a premium that erases whatever cash flow remains.

Vacancy Rates and Rent Trends: The Hidden Cash-Flow Killers

Two numbers quietly eat returns more than any other: vacancy and rent trajectory. Both are pointing the wrong direction in 2026.

The U.S. rental vacancy rate hit 7.3% in Q1 2026, up from 7.1% a year earlier, according to the Census Bureau's Housing Vacancy Survey. National median rent has fallen roughly 5% from its 2022 peak and was off 1.7% year-over-year as of April 2026, per Apartment List. Translation: the wind is in your face. You can't model a 5% vacancy rate and 3% annual rent growth like the spreadsheets did in 2021. The base case has changed.

Run every deal through a three-part stress test before you sign:

1. Rate stress: What happens if your refinance in five years lands at 8.5% instead of 7.25%? On a $225,000 loan, that's roughly $185 more per month in mortgage payment — does the deal survive? 2. Vacancy stress: What if vacancy hits 10%, not the 7.3% national average? On $39,600 in annual rent, that's an extra $1,069 in lost income. 3. Rent stress: What if market rents fall 5% over three years instead of staying flat? On the same property, you'd be down $1,980 a year by year three.

If the deal still produces positive cash flow under all three pressures, it's a real investment. If any single stressor flips it red, you're betting on conditions improving — and "betting on conditions improving" is not an investment thesis.

The other line item that quietly destroys returns: operating expenses. Multifamily operating expenses per unit averaged $8,657 in 2024, per the National Apartment Association's Survey of Operating Income & Expenses, with repairs and maintenance up more than 28% since 2021. Most pro formas still use 2019 expense ratios. They shouldn't. The 50% rule we mentioned earlier — assume operating expenses eat 50% of gross rent before mortgage payments — is a far better starting point in 2026 than the 35%–40% assumptions that floated around the last cycle.

How to Apply These Numbers: A 5-Step Action Plan

Here's how to run a property through all five numbers in under 30 minutes:

Step 1 — GRM screen (2 minutes). Get the asking price, get the realistic monthly rent (use Zillow Rent Estimate, Rentometer, and a local property manager — average them). Divide annual rent by price. If GRM is above 10 in a non-primary market, walk. Below 9, keep going.

Step 2 — Rent-to-price test (1 minute). Multiply purchase price by 0.011 to get your minimum monthly rent target. If realistic rent is below 1.1%, this property won't cash flow at 7.25% mortgage rates without a significant down payment or value-add plan. Self-managers can drop to 0.8%–1.0% but should expect minimal monthly profit.

Step 3 — Cap rate vs. mortgage rate (5 minutes). Pull the seller's actual operating expenses (or estimate at 45%–50% of rent if you don't trust them). Subtract from gross rent to get net operating income. Divide by purchase price. If your cap rate is below your mortgage rate (likely), make sure your business plan includes raising rents, cutting expenses, or holding for appreciation — not pure cash flow.

Step 4 — Cash-on-cash projection (10 minutes). Build a simple year-one cash flow: gross rent, minus 7.3% vacancy, minus 45%–50% operating expenses, minus annual mortgage P&I (use Bankrate's mortgage calculator or any equivalent at current rates). Divide annual cash flow by total cash invested (down payment + closing costs + reserves). Below 8%, the deal is probably a "no" unless you're betting heavily on appreciation. Above 12%, double-check your numbers — especially CapEx reserves and property management fees.

Step 5 — DSCR check (10 minutes). Take the same NOI from Step 3 and divide by annual debt service. Lenders want 1.00 minimum, 1.25+ for the best rates. If your DSCR comes in under 1.00, the property isn't financeable on standard investment terms — you'll need a bigger down payment, a different property, or a different loan product entirely.

If the deal passes all five gates, run the three-part stress test from the previous section. If it survives that too, you've found something most buyers won't — a deal that actually pencils out at 2026 cost of capital.

One last filter the math can't catch: qualitative red flags. Rent control, pending HOA litigation, special assessments, declining school district enrollment, single-employer towns, and local code changes can all override perfectly clean numbers. Read the HOA minutes. Pull the city's planning agenda. Talk to the previous tenant if you can. The five numbers tell you whether the math works. The qualitative checks tell you whether the math will keep working.

What to Read Next

If higher rates are reshaping how you think about a rental purchase, the same dynamics are reshaping the rest of the housing market — including who can afford to buy and where rents are still falling. These two pieces dig deeper into the same shift: Where Rents Are Falling in 2026 (and Where to Move) and What Income Do You Need to Own a Home in 2026?.

Recommended reading: What to Read Next

Sources

• Freddie Mac, Primary Mortgage Market Survey (via FRED): https://fred.stlouisfed.org/series/MORTGAGE30US
• FRED, 10-Year Treasury Constant Maturity Rate: https://fred.stlouisfed.org/series/DGS10
• CBRE, North America Cap Rate Survey: https://www.cbre.com/insights/reports
• U.S. Census Bureau, Housing Vacancy Survey (Q1 2026): https://www.census.gov/housing/hvs/
• Apartment List, National Rent Report (April 2026): https://www.apartmentlist.com/research/national-rent-data
• Tax Foundation, Facts & Figures: https://taxfoundation.org/publications/facts-and-figures/
• JPMorgan Commercial Term Lending, Cap Rates Explained: https://www.jpmorgan.com/insights/real-estate/commercial-term-lending/cap-rates-explained
• National Apartment Association, Survey of Operating Income & Expenses: https://www.naahq.org/research-insights
• Bankrate Mortgage Calculator: https://www.bankrate.com/mortgages/mortgage-calculator/

Data as of April 2026. Investment property mortgage rates, cap rates, and rent figures move continuously — verify current numbers before underwriting any deal.

This article is informational and not financial advice. Real estate investing involves risk; consult a licensed financial advisor, attorney, and CPA before making investment decisions.

Check your credit score for free — Kapitalwise

Subscribe to The Canopy Brief for weekly insights on building a richer life.

Found an error? At Canopy Press, accuracy comes first. If you spot a claim that needs checking, let us know at [email protected] — we'll verify and correct it immediately.

Found an error? At Canopy Press, accuracy comes first. If you spot a claim that needs checking, let us know at [email protected] — we'll verify and correct it immediately.

Sources

• Rentana — What is a Good Cap Rate for a Multifamily Property in 2026
• Rod Khleif — Cap Rates for Multifamily 2026: Benchmarks by City
• Apartment Loan Store — Cap Rates for Apartment/Multifamily Properties 2026
• JPMorgan Chase — Cap Rates, Explained
• The Mortgage Reports — Investment Property Mortgage Rates May 2026
• Rent To Retirement — Investment Property Mortgage Rates April 2026
• Evernest — The 1% Rule Is Dead in 2026
• REI Prime — Rent-to-Price Ratio: A Better 1% Rule
• DealForge — What Is a Good Cash-on-Cash Return? 2026 Benchmarks
• Origin Investments — Cash on Cash Return 2026