Real Estate Investing Metrics: Cap Rate, Cash-on-Cash, IRR, and More

Why metrics matter

Real estate deals are usually marketed in stories. The numbers are what tell you whether the story is true. Five metrics — cap rate, cash-on-cash return, IRR, GRM, and the heuristic 1% and 50% rules — together give a clear picture of any income property. Each has a specific use, each has limitations, and most amateur investors look at one or two when they should be looking at all of them.

Cap rate

Net operating income ÷ property value. Pre-debt, pre-tax. Used to compare yields across markets and asset classes. See our full cap rate guide for the deep dive.

Best for: comparing properties in similar markets, valuing income property using the inverse formula (Value = NOI / Cap Rate). Worst for: comparing leveraged deals, comparing across different financing structures.

Cash-on-cash return

Cash-on-Cash = Annual Pre-Tax Cash Flow ÷ Total Cash Invested

Cash invested includes down payment, closing costs, and initial rehab. Annual pre-tax cash flow is rent (after vacancy) minus all operating expenses minus debt service. Cash-on-cash is the return on the actual dollars you put into the deal, which matters because rental investing is almost always leveraged.

Example: $80,000 down + $5,000 closing + $15,000 rehab = $100,000 invested. Annual cash flow of $10,000 = 10% cash-on-cash. Most rental investors target 8–12% cash-on-cash in stabilized deals.

IRR (internal rate of return)

IRR is the annualized total return on an investment, including ongoing cash flow, equity build, and sale proceeds. It's the most complete return metric because it accounts for the time value of money and the entire holding period.

Computing IRR requires modeling cash flows for every year of ownership through eventual sale. The result tells you what annual return the investment is delivering, comparable to stock or bond returns. Most professional buyers think in IRR; most retail investors don't, which is part of why pricing in retail single-family rentals can be irrational.

Typical target IRRs depend on risk: 8–10% for stabilized core multifamily, 12–15% for value-add multifamily, 18%+ for distressed or development deals.

GRM (gross rent multiplier)

GRM = Property Price ÷ Annual Gross Rent

GRM is the simplest screening metric — just price divided by annual rent. A property at $250,000 with $30,000 of annual rent has a GRM of 8.3. Lower GRM means more rent per dollar of price. GRM doesn't account for expenses, so a 7 GRM in a high-tax state can be worse than an 8 GRM in a low-tax state.

GRM is most useful for quick screening of a large number of properties. Once you've narrowed down to a few candidates, switch to cap rate and cash-on-cash for real decisions.

The 1% rule

The 1% rule says monthly gross rent should be at least 1% of the purchase price. A $250,000 house should rent for $2,500+/month. Properties meeting the 1% rule usually cash flow comfortably after expenses and debt service.

In current US markets, the 1% rule is extremely rare in coastal metros and reasonably common in Midwest and Southeast secondary markets. Investors who insist on 1% miss out on appreciation markets; investors who ignore it entirely accept thin cash flow. Most experienced investors target 0.7–1.0% in growth markets and 1.0–1.5% in cash-flow markets.

The 50% rule

The 50% rule says operating expenses (taxes, insurance, repairs, vacancy, management, lawn, utilities) run about 50% of gross rent over the long term. So a property with $2,500/month of gross rent should expect about $1,250/month of operating costs, leaving $1,250 to cover the mortgage and produce cash flow.

Like all heuristics, the 50% rule is approximate. Higher-end SFRs may run 35–40% of rent in expenses. Older multifamily may run 55–60%. Use it as a sanity check on a deeper proforma, not as the actual budget.

Combining metrics

No single metric tells the whole story. A property might have a 6% cap rate (decent), 12% cash-on-cash (good with leverage), 15% projected IRR (strong), and miss the 1% rule (no big deal if cash-on-cash is hitting). Together those numbers describe an attractive deal.

The danger is fixating on one number. A 1.5%-of-price rent ratio in a declining Rust Belt market may pencil on day-one cash flow but lose money to value depreciation over 10 years. A 0.7%-of-price ratio in Austin may underperform on year-one cash flow but compound to a strong IRR through rent growth and appreciation. Use the right metric for the right question.