Is Your Rental Actually Making Money?
The landlord's complete financial model: NOI, cap rate, and cash-on-cash return — what each number means, how to calculate them, and what they reveal about your portfolio.
The Three Numbers Every Landlord Must Know
There is a common landlord misconception that goes like this: "My mortgage is $1,200/month and I charge $1,844 in rent, so I make $644/month." This is wrong — and landlords who believe it consistently underestimate costs, overpay for properties, and make poor decisions about when to sell. The correct framework uses three numbers: Net Operating Income, Cap Rate, and Cash-on-Cash Return. Each tells you something different. None is complete alone.
Net Operating Income (NOI)
NOI is the income your property generates after operating expenses, before debt service. It's the foundation of every other calculation and the number most institutional buyers use to value properties.
Formula: NOI = Gross Rental Income − Vacancy − Operating Expenses
Operating expenses include property taxes, insurance, maintenance, property management fees, HOA fees, and any utilities you pay. They do not include mortgage principal or interest — debt service is not an operating expense. A 5% vacancy rate and 40% expense ratio is a reasonable starting point for a single-family rental in 2026.
Cap Rate
Cap rate tells you the return the property would generate if you owned it free and clear. It allows comparison between properties regardless of how they're financed — making it the standard valuation metric for investment real estate.
Formula: Cap Rate = NOI ÷ Current Market Value
In most major markets in 2026, residential cap rates run 4–7%. Below 4% signals you're paying a premium — likely for appreciation potential in a high-demand submarket. Above 7% often signals higher risk, deferred maintenance, or a less desirable location. Neither is necessarily wrong, but you should know which situation you're in.
Cash-on-Cash Return
Cash-on-cash is your actual annual return on the dollars you personally invested — your down payment and closing costs. This is the number that matters most to leveraged investors because it accounts for your mortgage payment.
Formula: CoC = Annual Pre-Tax Cash Flow ÷ Total Cash Invested
| Metric | What It Measures | 2026 Target Range |
|---|---|---|
| NOI | Property income before debt service | Benchmark against comparable properties |
| Cap Rate | Return if owned free and clear | 5–7% residential in most markets |
| Cash-on-Cash | Return on actual invested dollars | 8–12% for residential |
| GRM | Quick valuation ratio | Under 12 is generally favorable |
The Expense Ratio Most Landlords Get Wrong
The single most expensive mistake in rental financial modeling is underestimating expenses. Landlords who use 20–25% expense ratios consistently run negative cash flow when reality hits. A more accurate rule: 40–50% of gross rents covers all operating expenses over time for a single-family home. If your numbers only work at 20% expenses, the deal probably doesn't work.
Assume 50% of gross rent goes to operating expenses over the long run. Whatever remains after debt service is your actual cash flow. If that number is negative using the 50% rule, walk away from the deal.
Financial Audit Checklist
Real-time parcel data, rent comps, and market intelligence for every address in America.
Get API Access →