The capitalization rate — or cap rate — is one of the most widely used metrics in real estate investing. It tells you how much annual income a property generates relative to its purchase price, expressed as a percentage. Before you make an offer on any investment property, you need to know this number.

The cap rate won't tell you everything, but it gives you a fast, standardized way to compare properties across different markets, price points, and property types — without financing assumptions clouding the picture.

The Cap Rate Formula

Cap Rate = Net Operating Income ÷ Property Value × 100
Or: NOI / Current Market Value = Cap Rate (%)

Two variables drive this formula. First, Net Operating Income (NOI) — which is your gross rental income minus all operating expenses, but before debt service. Second, property value — either the purchase price or the current market value depending on what you're calculating.

Step-by-Step: Calculating Cap Rate

Step 1 — Calculate Gross Annual Rent

Start with what the property produces at full occupancy. If a property rents for $2,200/month, gross annual rent is $2,200 × 12 = $26,400. Don't include future rent increases or optimistic assumptions at this stage.

Step 2 — Apply a Vacancy Factor

No rental property stays 100% occupied every year. A standard vacancy allowance is 5–8% for most stabilized markets. In high-demand urban areas, 3–5% is reasonable. In slower markets, use 8–10%. On $26,400 gross rent with a 7% vacancy assumption, your effective gross income drops to $24,552.

Step 3 — Subtract Operating Expenses

Operating expenses are everything that costs money to run the property, excluding mortgage payments. Common categories include:

A common rule of thumb is that operating expenses run 35–50% of gross rental income for single-family rentals. For multifamily, they tend to run slightly higher. Use real numbers from the seller's records whenever possible — and verify them.

Step 4 — Calculate NOI

NOI = Effective Gross Income − Operating Expenses

Example — $325,000 Single-Family Rental
Gross Annual Rent$26,400
Less Vacancy (7%)−$1,848
Effective Gross Income$24,552
Property Taxes−$3,200
Insurance−$1,100
Property Management (10%)−$2,455
Repairs & Maintenance−$1,800
CapEx Reserve−$1,200
Net Operating Income (NOI)$14,797
Cap Rate ($14,797 ÷ $325,000)4.55%

What Is a Good Cap Rate?

There is no universal "good" cap rate — it depends entirely on the market, property type, and your investment goals. That said, here are common benchmarks:

Key insight: Cap rate and property price move inversely. When buyers pay more for the same income stream, the cap rate compresses. A rising cap rate environment (like higher interest rate periods) means property values tend to fall even if rents stay flat.

Cap Rate vs. Cash-on-Cash Return

Cap rate ignores financing. It measures the property's performance as if you bought it with all cash. Cash-on-cash return, on the other hand, measures your actual return on the dollars you invested — including the effect of your mortgage.

Use cap rate to compare properties on an apples-to-apples basis. Use cash-on-cash return to evaluate your actual leveraged returns based on your specific financing terms. Both metrics belong in every deal analysis.

What Cap Rate Doesn't Tell You

Cap rate is a snapshot metric, not a complete picture. It doesn't account for:

Always pair your cap rate analysis with a full cash flow model and a look at the property's physical condition. A 9% cap rate on a property that needs $50,000 in deferred maintenance is not what it appears to be.

How to Use Cap Rate When Making Offers

If you know the NOI of a property and have a target cap rate in mind, you can work backward to determine what you should pay. This is called income-based valuation:

Max Purchase Price = NOI ÷ Target Cap Rate
Example: $14,797 NOI ÷ 0.06 target cap rate = $246,617 max price

This approach gives you an offer ceiling grounded in financial performance, not emotion. It's especially powerful when negotiating with sellers who are pricing on comparable sales rather than income.