Lease glossary

Net operating income (NOI)

Net operating income, or NOI, is a rental property’s yearly income after vacancy and operating expenses, but before mortgage payments, depreciation and income tax. It is the number behind cap rate and behind most buyer and lender valuations of a rental.

Example

A triplex rents for $3,000 a month, $36,000 a year. Allow 5% for vacancy ($1,800), leaving $34,200. Operating expenses are property tax $4,200, insurance $1,500, repairs $3,000, utilities $1,200 and management at 8% of collected income ($2,736): $12,636 in all. NOI is $34,200 − $12,636 = $21,564. At a 6% cap rate, that NOI supports a value of about $359,400.

In an operating statement it looks like…

Trailing 12 months: gross scheduled rent $36,000; vacancy and credit loss $1,800; operating expenses $12,636; net operating income $21,564.

Good to know

Leave out the mortgage, depreciation and big one-off improvements like a new roof: those belong to the owner’s financing and tax picture, not to how the property runs. A seller’s NOI that skips vacancy or management, or uses this year’s low tax bill before a reassessment, flatters the price. Careful buyers rebuild NOI from the leases and the tax bill themselves.

Plain English, not legal advice. Last reviewed September 29, 2026.