How to Calculate Cap Rate (and When the Number Lies)

How to Calculate Cap Rate (and When the Number Lies)

The capitalization rate is the most quoted number in real estate — and one of the most casually abused. The calculation takes ten seconds; knowing what the result actually means, and when it is actively misleading you, is the skill. This guide covers both: the formula with worked examples, the going-in versus terminal distinction that most explainers skip, and the specific situations where a cap rate lies.

All figures below are illustrative examples, not market data. If you want the one-page version to keep next to your screen, download the free cap rate cheat sheet — the formula, the three solves, the NOI checklist, and the red-flag list, on a single reference page.

The Cap Rate Formula

Cap Rate = Net Operating Income ÷ Property Value

In words: the unlevered yield a property's current income produces on its price. A property generating $180,000 of NOI on a $3,000,000 valuation is trading at a 6.0% cap — its income is 6% of its price, before any financing.

Worked example one — pricing a listing. A broker markets a 30-unit building at $4,200,000 with a stated NOI of $252,000. Cap rate = $252,000 ÷ $4,200,000 = 6.0%. Whether that is attractive depends entirely on what comparable properties trade at — the number has no meaning in isolation.

Worked example two — valuing from income. Your underwriting says a property will produce $195,000 of stabilized NOI, and adjusted comparable sales in the submarket support a 6.5% cap. Implied value = $195,000 ÷ 0.065 = $3,000,000. This is the formula run in reverse — the basis of the direct capitalization method, covered in depth in the direct capitalization method explainer.

Worked example three — testing a price. A seller asks $2,600,000 in a market where the asset type trades around 6.25%. Required NOI = $2,600,000 × 0.0625 = $162,500. If the property's honest NOI is $140,000, the asking price embeds either a below-market cap rate or income the property does not yet produce — and now you know which question to ask.

For the interactive version of all three solves, plus the Excel formulas to build them yourself, use the free cap rate calculator.

Getting the Inputs Right

The formula never produces a wrong answer; the inputs do. Two rules carry most of the weight:

NOI must be true NOI. Effective gross income (rent after vacancy and credit loss, plus other income) minus operating expenses — including a market-rate management fee — and excluding debt service, income taxes, depreciation, and capital expenditures. The classic distortions all live here: gross income passed off as NOI, management omitted because the owner self-manages, chronically deferred maintenance flattering the expense line.

Value must match the question. For a going-in cap on an acquisition, use the purchase price (decide, and disclose, whether closing costs are in — conventions differ). For portfolio marking or refinance analysis, use current appraised value. Mixing bases across comparisons quietly corrupts the analysis.

Going-In vs. Terminal: The Distinction That Matters

Every full underwriting uses the cap rate twice, and the two uses point in opposite directions:

The going-in cap rate prices the acquisition: first-year (or in-place) NOI over the purchase price. It answers what am I paying for this income today.

The terminal (exit) cap rate prices the sale at the end of the hold: the model's projected forward NOI at exit, divided by the assumed terminal cap, produces the reversion value — typically the largest single cash flow in the deal.

The relationship between them is one of the most consequential assumptions in any pro forma. Assuming the exit cap equals the going-in cap assumes the market pays the same price for your income stream a decade from now, on an older building. Assuming exit cap compression — selling at a lower cap than you bought — bakes a favorable market move into your returns. The conservative convention is modest exit-cap expansion: assume the exit cap somewhat above the going-in cap, so the return is carried by the income and the business plan rather than by market timing. A deal that only works with cap compression is a market bet wearing an underwriting costume.

What Is a Good Cap Rate?

The honest answer: there is no universal good cap rate, because the cap rate is a price, and prices are relative.

A cap rate compresses three judgments into one number — the riskiness of the income, its expected growth, and the return available on competing uses of capital. Lower cap rates mean the market pays more per dollar of income: typically newer assets, stronger locations, more durable tenancy, better growth prospects. Higher cap rates mean cheaper income with more risk or less growth attached. Neither is "better"; they are different products at different prices.

Three usable anchors in place of a magic number:

1. Adjusted comps. The defensible benchmark is what comparable properties — adjusted for condition, location, occupancy, and NOI convention — actually traded at in your submarket recently.
2. The spread over financing. Compare the cap rate to your borrowing cost. When the cap rate exceeds the loan constant, leverage adds to cash-on-cash returns (positive leverage); when it is below, debt consumes cash flow (negative leverage) and the deal is a growth bet by construction.
3. Your alternatives. A cap rate is a yield; it competes with every other yield available to your capital, adjusted for risk, illiquidity, and effort.

Why Cap Rates Differ Across Properties

Before the red-flag list, it helps to see why two honest cap rates can legitimately differ — because the lies in the next section all work by imitating these legitimate differences.

Cap rates spread along a risk-and-growth spectrum. Within a single market, newer assets in stronger locations with durable tenancy trade at lower caps than older assets in weaker locations with churning tenancy — the market pays a premium (accepts a lower yield) for income it trusts. Across asset classes, the same logic applies: property types with steadier demand and lower re-leasing risk generally price tighter than those with volatile income. And across time, cap rates drift with the cost of capital, since a property's yield competes with bonds and with the debt used to buy it.

None of this is mispricing; it is pricing. The skill is distinguishing a cap rate that is high because the income is genuinely riskier — a fair discount — from one that is high because the NOI is fictional, the capex is hidden, or the comp set is wrong. Which brings us to the lies.

When the Cap Rate Lies

The number misleads in predictable, recurring situations. The red-flag list:

1. Pro forma dressed as in-place. The single most common lie. A "6.5% cap" computed on the seller's projected post-renovation NOI can be a low-5s cap on the income the property produces today. Always ask which NOI the quoted rate is built on, and compute both.

2. Non-standard NOI. No management fee, artificially low maintenance, gross income in the numerator, real estate taxes at the seller's legacy assessment rather than the reset your purchase triggers. Each flatters the rate. The tax item deserves numbers, because it is both the largest and the most mechanical: a property marketed at a 6.5% cap on $260,000 of NOI and a $4,000,000 price may carry taxes assessed on the seller's decade-old basis. If your purchase resets the assessment and adds $40,000 of annual tax, the honest NOI is $220,000 and the real going-in cap is 5.5% (illustrative) — a full point of yield that existed only in the seller's tax bill. Rebuild NOI yourself before trusting any quoted cap.

3. Capital-hungry assets. Cap rate sits above capital expenditures, so two properties with identical NOI show identical caps even if one needs a roof, elevators, and systems in the next five years. On older assets, a seductive cap rate is often just deferred capex wearing makeup. Some buyers compute an "all-in" yield on price plus near-term capital needs precisely to strip this distortion.

4. Income durability mismatches. A property with one tenant and four years of lease term can print the same cap rate as one with staggered long-term credit leases. Identical number, radically different risk. Cap rate measures the size of the income, not its security.

5. Value-add and vacancy situations. On a half-empty building, in-place cap rate is nearly meaningless — the deal is priced on the path to stabilization. Here the better lenses are price per unit or per square foot, and stabilized yield on total cost.

6. Cross-market and cross-vintage comparisons. A higher cap in a weaker market is not "cheaper" than a lower cap in a stronger one — it is a different risk-growth bundle. The rate only ranks properties within a genuinely comparable set.

The pattern across all six: the cap rate is a snapshot of one year's income against a price. Whenever the story of the deal lives in the future — growth, renovation, lease-up, capital needs, exit — the snapshot cannot see it. That is what the 10-year model and the IRR are for, and the division of labor between the two metrics is the subject of cap rate vs. IRR.

Frequently Asked Questions

How do I calculate cap rate on a rental property? Annual NOI (collected rent and other income, minus vacancy allowance and all operating expenses including management, excluding mortgage payments) divided by the property's price or value. A house renting for $2,000/month with $9,000 of annual operating costs and a 5% vacancy allowance produces NOI of $2,000 × 12 × 0.95 − $9,000 = $13,800; at a $230,000 price that is a 6.0% cap (illustrative).

Is cap rate the same as ROI or cash-on-cash return? No. Cap rate is unlevered and property-level. Cash-on-cash measures your levered cash flow against your invested equity, and ROI variants blend in appreciation and principal paydown. Same deal, three different numbers answering three different questions.

Do I include the mortgage in a cap rate calculation? No — NOI is computed before debt service. That is deliberate: it makes the metric comparable across buyers regardless of financing.

What does a 7% cap rate mean? The property's annual net operating income equals 7% of its price — roughly, fourteen years of current NOI would sum to the purchase price, ignoring growth. Whether 7% is rich or cheap depends entirely on the comparable set.

Why do cap rates move when interest rates move? Because cap rates compete with other yields and are anchored to the cost of the debt used to buy property. When financing costs rise, buyers require more income per dollar of price, which pressures cap rates upward — with a lag, and unevenly across markets and asset classes.

Keep the Formula — and the Red Flags — at Hand

Download the free cap rate cheat sheet for the formula, the three solves, the NOI inclusion checklist, and the six lies on one page.

When you are ready to run the analysis properly, the Cap Rate & Property Valuation Toolkit implements everything in this guide in Excel: the three-way solver, a comps-adjustment grid, direct capitalization valuation, and the cap-rate sensitivity table — fully unlocked, formula-transparent, with a documented methodology PDF. The full model catalog is in the store.

This article is for educational purposes only and does not constitute investment, legal, or tax advice. All figures are illustrative examples, not market data. Consult qualified professionals before making investment decisions.