You found a property listing that looks promising. The photos are nice, the neighborhood seems solid, and the price feels right. But “feels right” is not a strategy. It is how people lose money in real estate.
Before you write an offer on any rental property, you need to run the numbers. Not just some of the numbers. All of them. I have watched too many first-time investors fall in love with a property only to discover six months later that their “investment” is costing them $400 a month out of pocket.
This guide will teach you exactly how to evaluate a rental property like a professional investor. No MBA required. Just a calculator and the willingness to do the math before you do the deal.
The 5 Numbers That Matter
Every experienced investor I know evaluates properties using the same core metrics. Learn these five numbers and you will be ahead of 90% of first-time buyers.
1. Cap Rate (Capitalization Rate)
The cap rate tells you what percentage return you would earn if you bought the property with all cash. It strips out financing and shows you the raw earning power of the asset.
Formula: Net Operating Income (NOI) / Purchase Price = Cap Rate
For example, if a property generates $12,000 per year in net operating income and costs $200,000, the cap rate is 6%.
What is a good cap rate? It depends on your market. In Salt Lake City, a 5-7% cap rate on a residential rental is solid. In smaller Midwest markets, you might find 8-10%. In expensive coastal cities, 3-4% is common.
Important: A high cap rate is not always better. It often signals higher risk, rougher neighborhoods, or deferred maintenance. Context matters.
2. Cash-on-Cash Return
This is the number most investors actually care about because it accounts for your financing. It tells you what percentage return you are earning on the actual cash you invested (your down payment, closing costs, and any rehab).
Formula: Annual Cash Flow / Total Cash Invested = Cash-on-Cash Return
If you put $50,000 into a deal (down payment plus closing costs) and the property generates $5,000 per year in cash flow after all expenses including the mortgage, your cash-on-cash return is 10%.
I tell my students to target a minimum 8% cash-on-cash return. Below that, you might be better off in index funds with far less headache.
3. The 1% Rule (Quick Screening Tool)
The 1% rule is a fast filter, not a final answer. It says that a property’s monthly rent should be at least 1% of its purchase price.
A $200,000 property should rent for at least $2,000 per month. A $150,000 property should rent for at least $1,500.
If a property does not meet the 1% rule, it does not automatically mean you should walk away. But it does mean you need to look more carefully at the numbers. In expensive markets, very few properties hit 1%, and investors make money through appreciation instead of cash flow.
For cash flow investors (which is what I recommend for beginners), the 1% rule is your first screening tool. If a property is at 0.5%, keep scrolling.
4. Expense Ratio
New investors consistently underestimate expenses. They calculate rent minus mortgage and call the difference “profit.” That is a recipe for financial pain.
A realistic expense ratio for a residential rental is 40-50% of gross rent. Yes, half your rent goes to expenses. Here is where it goes:
- Property taxes (varies by location, typically 1-2% of property value annually)
- Insurance (landlord policy, typically $800-1,500/year)
- Maintenance (budget 5-10% of rent)
- Capital expenditures (roof, HVAC, water heater; budget 5-10% of rent)
- Vacancy (budget 5-8% of rent, even in hot markets)
- Property management (8-10% of rent if you hire a manager)
When I teach deal analysis in my Legacy at the Table course, I always use a 50% expense ratio as the starting point. It is better to be pleasantly surprised than financially devastated.
5. Debt Service Coverage Ratio (DSCR)
Your DSCR tells you how comfortably your property can cover its mortgage payment from rental income. Lenders use this number, and you should too.
Formula: Net Operating Income / Annual Mortgage Payment = DSCR
A DSCR of 1.0 means you are breaking even. Below 1.0 means you are losing money. Above 1.25 means you have a comfortable cushion.
I recommend targeting a DSCR of at least 1.25 for your first property. You want margin for the unexpected, because the unexpected always shows up.
Red Flags That Kill Deals
Even if the numbers look good on paper, watch for these deal breakers:
- Foundation issues: Cracks wider than a quarter-inch, doors that will not close, sloping floors
- Environmental concerns: Flood zones, old underground storage tanks, lead paint in pre-1978 homes
- Declining neighborhood: Rising vacancy rates, falling home values, major employer leaving the area
- Deferred maintenance: If the roof, HVAC, plumbing, and electrical all need replacement, that “great price” is not so great
- Unrealistic seller projections: If the seller says the property “could” rent for $2,000 but current tenants pay $1,400, use the actual number
Running Your First Analysis: A Step-by-Step Example
Let us walk through a real example. You find a duplex listed at $250,000. Each unit rents for $1,300/month, so your gross monthly rent is $2,600.
1% rule check: $2,600 / $250,000 = 1.04%. Passes.
Annual gross rent: $31,200
Estimated expenses (50%): $15,600
Net Operating Income: $15,600
Cap rate: $15,600 / $250,000 = 6.24%. Solid.
Mortgage (20% down, 7% rate, 30 years): Approximately $1,330/month or $15,960/year
Annual cash flow: $15,600 – $15,960 = negative $360
Wait. The cap rate looked great, but after financing, you are actually losing money. This is exactly why you run all five numbers, not just one.
In this scenario, you would need to negotiate the price down, find a way to increase rents, or walk away. The numbers do not lie.
Your Next Step
Practice is everything. Pull up five listings in your target market this week and run the numbers on each one. Use a spreadsheet. Get comfortable with the math. By your tenth analysis, the process will feel natural.
And remember: the best deal is the one you do not do when the numbers say no.
Want the exact spreadsheet I use to analyze deals? Grab the Deal Analysis Spreadsheet ($37). It auto-calculates all five metrics, includes a side-by-side comparison tool for up to 10 properties, and comes with a video walkthrough so you know exactly how to use it.