What a Cap Rate Tells You About a Property

A cap rate — capitalisation rate — is net operating income divided by price. It is the standard shorthand for comparing income properties, and its usefulness comes entirely from what it deliberately excludes.

It says nothing about your mortgage, your tax position or your holding period. That is a feature, not a gap, and misreading it as a return on your money is the most common error.

What the number is measuring

Net operating income is rental income minus operating expenses — taxes, insurance, maintenance, management, utilities you pay, and a vacancy allowance.

Debt service is not an operating expense. Neither is depreciation, nor capital improvements.

Divide that figure by the purchase price and you get the cap rate. Because financing is excluded, the same property produces the same cap rate whether bought with cash or with heavy borrowing. That is exactly what makes it useful for comparing properties: it describes the asset, not the buyer.

It also means the number is not your return. Your return depends on how you financed it, which is what cash-on-cash return measures instead.

The cap rate calculator works it from income and expenses, and the rental cash flow calculator adds the financing layer.

A high cap rate is usually a warning

The instinct is that higher is better. Often the opposite is true, because the figure is a price the market has set for a risk.

A high one means buyers demanded a large income yield to accept the property. That usually reflects something: a weak or declining local economy, poor tenant quality, an older building with deferred maintenance, a thin resale market, or a lease about to expire.

A low one means buyers accepted a small yield, usually because they expect rent growth, appreciation, or unusually low risk.

So the number is closer to a risk premium than a quality score. Comparing a high yield in a declining area against a low one in a growing city and concluding the first is better ignores what the difference is compensating for.

The comparison only works within a market and property type. Across markets, the spread is information about the markets, not about which purchase is smarter.

Where the number gets manipulated

Because the numerator is an estimate, the ratio is easy to inflate, and listing materials routinely do.

Understated vacancy. A pro forma showing full occupancy every month is not a forecast, it is an assumption nobody achieves. The vacancy cost calculator shows what a realistic allowance does — and it is one of the largest swing factors in the whole calculation.

No management fee. If you self-manage, you are still doing work worth paying for. Omit it and you have inflated the income by the value of your own labour, which also overstates the price a future buyer would pay.

No maintenance reserve. Roofs, systems and appliances fail on a schedule even if they did not fail this year. A pro forma with only last year's actual repairs understates long-run cost.

Market rents rather than actual rents. "Rents could be raised to X" is a plan, not income.

Capital improvements treated as operating expenses, or vice versa, depending on which flatters the number.

The defence is to rebuild the net operating income yourself from actual figures — tax bills, insurance quotes, real rent rolls — rather than accepting the seller's. A yield computed on optimistic inputs is precise and meaningless.

What it deliberately leaves out

Even a correctly computed figure is missing several things that determine whether a purchase works.

Financing. The largest omission. A property yielding 6% bought with debt at 7% loses money every month despite looking healthy. When borrowing costs exceed the yield, leverage works against you — the effect that catches buyers who learned the metric during a low-rate period.

Appreciation. A single-year snapshot says nothing about growth, and in strong markets appreciation frequently exceeds income as a source of return.

Tax treatment. Depreciation shelters income, which improves after-tax returns substantially — and creates depreciation recapture on sale. The cost basis guide covers how that accumulates.

Capital expenditure. Not an operating expense, but real money on a real schedule.

Your time. Managing property is work.

Liquidity. Property cannot be sold quickly at a known price.

Using it well

Use it to screen, not to decide. It is a fast filter for whether a property is priced within range of comparable ones, not an investment analysis.

Compare like with like. Same market, same property class, same condition, same computation method.

Compute it on the price you would pay, including closing costs and immediate repairs — not on the asking price.

Compare it against the borrowing rate. The spread between the yield and your interest rate is the first indication of whether leverage helps or hurts.

Then move to the metrics that include you. The one percent rule is a cruder screen that works faster; cash-on-cash return tells you what your money earns; and a full rental cash flow projection is what actually decides whether the property is worth owning.

One final use worth knowing: the cap rate also prices exit. Because value equals income divided by cap rate, a property bought at a 5% cap and sold at a 7% cap loses value even if income grew. Cap rate expansion is a real risk in a rising-rate environment, and it is the reason buyers underwrite a higher exit cap rate than the one they bought at.