How Rental Property Returns Are Calculated
Three metrics define a rental deal: cap rate, cash-on-cash return, and monthly cash flow. Cap rate measures the property's income potential independent of financing. Cash-on-cash return measures what your actual invested dollars earn. Cash flow is what hits your bank account each month.
Cap Rate = Net Operating Income / Purchase Price. NOI is your annual rental income minus operating expenses (property tax, insurance, maintenance, management, vacancy)—but before mortgage payments. A $300,000 property with $16,200 NOI has a 5.4% cap rate. Higher cap rates mean higher returns but often signal higher-risk areas.
Cash-on-Cash Return = Annual Cash Flow / Total Cash Invested. Unlike cap rate, this factors in your mortgage. If you put $75,000 down and net $5,760/year after all expenses including the mortgage, your cash-on-cash is 7.7%. Most investors target 8–12%.
Monthly Cash Flow = Effective Rent − Total Expenses. Effective rent accounts for vacancy (typically 5–8%). Total expenses include mortgage principal & interest, property tax, insurance, maintenance, property management, and any other recurring costs.
Cap Rate Benchmarks by Market Type
| Market Type | Typical Cap Rate | Example Cities |
|---|---|---|
| High-Cost Coastal | 3–5% | San Francisco, NYC, LA, Seattle |
| Mid-Tier Metro | 5–8% | Dallas, Atlanta, Nashville, Denver |
| Smaller Markets | 8–12% | Memphis, Cleveland, Birmingham, Tulsa |
| Multi-Family | 5–10% | Varies by unit count and market |
A higher cap rate is not automatically better. A 10% cap rate in a declining neighborhood carries more risk than a 5% cap rate in a stable suburban market with rising rents. Always pair cap rate analysis with local vacancy trends, job growth, and population data.
The 1% Rule and Other Quick Screening Tests
The 1% Rule: Monthly rent should equal at least 1% of the purchase price. A $200,000 property should rent for $2,000+/month. Properties meeting this threshold usually cash flow positive. In expensive markets, 0.7–0.8% is more realistic. In affordable markets, 1.5–2% is achievable.
The 50% Rule: Roughly half your rental income goes to operating expenses (excluding mortgage). If you collect $2,000/month in rent, expect about $1,000 for taxes, insurance, maintenance, vacancy, and management. Use this for back-of-envelope estimates before running full numbers.
| Screening Rule | Formula | Target |
|---|---|---|
| 1% Rule | Monthly Rent / Purchase Price | ≥ 1% |
| 50% Rule | Operating Expenses / Gross Rent | ≤ 50% |
| Cash-on-Cash | Annual Cash Flow / Cash Invested | ≥ 8% |
| Cap Rate | NOI / Purchase Price | ≥ 5% |
These rules are screening tools, not final verdicts. A property that fails the 1% rule might still be a great investment if appreciation is strong. A property that passes every rule might be a money pit if the roof needs $15,000 in repairs. Always run full numbers with this calculator before making an offer.
To calculate the mortgage portion of your rental expenses, use our mortgage calculator. Planning how much to put down? Try the down payment calculator. For a broader look at investment returns, check the ROI calculator.