Why Cap Rate Deliberately Ignores Your Mortgage

A deliberate omission, not an oversight

Cap rate's formula — net operating income divided by property value — conspicuously leaves out mortgage payments, even though they're one of the biggest real costs of owning a financed property. That's intentional: cap rate is designed to measure a property's return as if it were purchased entirely with cash.

Why that makes comparison possible

Two investors buying the identical property with different down payments, interest rates, and loan terms would see very different actual cash-on-cash returns — but the property itself generates the same income regardless of how either investor chose to finance it. Cap rate strips financing out specifically so two very differently financed buyers can compare the same property on equal footing.

What stays in the calculation

Net operating income (NOI) still subtracts real operating costs — property tax, insurance, maintenance, management fees — just not the loan payment itself: NOI = Gross Rental Income − Operating Expenses, then Cap Rate = NOI ÷ Property Value.

What it leaves for a separate analysis

Because financing is excluded, cap rate alone says nothing about whether a specific investor's actual cash flow after their mortgage payment will be positive or negative — that requires a separate cash-on-cash return calculation layered on top, using that investor's real loan terms.

Compare properties fairly

Our Cap Rate Calculator calculates NOI and cap rate from your property's income, expenses and value — a useful first-pass comparison, though not a complete investment analysis on its own.