Net operating income

What it means

Net operating income, universally abbreviated NOI, is a property's income after operating expenses but before financing, depreciation and capital spending.

The exclusions are the definition. NOI deliberately leaves out:

• Mortgage payments, both interest and principal — because financing is a fact about the owner, not about the property
• Depreciation — because no money moves
• Capital expenditure — because a roof is an investment in the asset, not a cost of running it
• Income tax — because it depends on the owner's circumstances

What is left measures the building itself. Two investors buying the same property, one with cash and one with an 80% loan, have wildly different cash flow and identical NOI. That is the entire point: NOI is the number you compare properties with, and cash flow is the number you live on.

The calculation:

Gross scheduled rent, less vacancy and credit loss, plus other income, less operating expenses — equals NOI.

Other income covers laundry, parking, storage and pet rent. Operating expenses cover property tax, insurance, repairs and maintenance, management, utilities you pay, and administrative costs.

Why it matters

NOI is the input to nearly every other property metric, so an error here propagates everywhere.

It drives valuation directly. Cap rate is NOI divided by price, so at a market cap rate of 6.62%, every extra $1,000 of annual NOI is worth about $15,100 of value. That relationship is why operating discipline compounds: a $60-a-month saving on insurance is $720 a year of NOI and roughly $10,900 of value.

It drives lending. Debt service coverage ratio is NOI divided by annual debt service, and lenders typically require 1.20 to 1.25. On the canonical property that is NOI of $20,530 against debt service of $13,782.60 — a ratio of 1.49, comfortably financeable.

And it drives comparison. Because NOI ignores financing, it is the only way to compare a property you would buy with cash against one you would leverage, or your own property against a listing.

The corresponding trap is treating NOI as spendable. It is not. On this property NOI is $20,530 and the actual cash left is $6,747.40, because the mortgage takes $13,782.60 of it. An investor who plans against NOI is planning against a number that has not yet paid the loan.

How it works in practice

Build it in the standard order, and be strict about what is an operating expense.

Annual NOI, canonical property	Amount
Gross scheduled rent, 2,400.00 × 12	28,800.00
Vacancy and credit loss	0.00
Effective gross income	28,800.00
Property tax and insurance	(4,180.00)
Repairs and maintenance	(1,850.00)
Management, legal, mileage, supplies	(2,240.00)
Total operating expenses	(8,270.00)
Net operating income	20,530.00

The operating expense ratio here is $8,270 ÷ $28,800 = 28.7%, which is on the efficient side for a self-managed single-family rental. Buildings with paid management, landlord-paid utilities or older systems commonly run 35% to 50%.

Three judgement calls decide whether an NOI is honest.

Vacancy. A property that was fully let this year will not be every year. Serious analysis applies a normal vacancy rate — 5% to 8% — rather than last year's actual. At 6.6%, this property's NOI drops to about $18,629.

Management. If you self-manage, an NOI with no management cost overstates what the property produces for anyone else. Adding a market rate of 8% — $2,304 — is what makes it comparable.

Reserves. NOI excludes capital expenditure by definition, but a property that needs a roof in three years is not producing $20,530 in any meaningful sense. Institutional practice deducts a replacement reserve; small landlords should at least know the number.

Applying all three gives a conservative NOI closer to $16,300 — the figure to underwrite against rather than the headline one.

Common mistakes

• Including the mortgage. The most common error, and it makes properties incomparable.
• Including depreciation. It belongs to the tax calculation, not the operating one.
• Including capital improvements. A new roof is not a cost of operating this year.
• Using actual vacancy from a good year. Normalise it.
• Omitting self-management. Free labour makes an NOI that only works while you are doing it.
• Treating NOI as cash. Debt service still has to come out.
• Excluding property tax. It is an operating expense, and reassessment after a purchase often raises it materially above the seller's figure.

How BareBones PM helps

NOI is a categorisation exercise. Every mistake above is an expense filed in the wrong bucket.

BareBones PM records expenses per property against categories that keep the distinctions NOI depends on: operating expenses separated from debt service, interest separated from principal, and capital improvements recorded as depreciable assets rather than as repairs.

Because those splits exist in the ledger rather than being applied afterwards, the same records produce NOI, cash flow and the year-end tax figures without three separate reconciliations.

Rent, vacancy and arrears come from the lease ledger, so effective gross income is based on what was actually collected rather than on the scheduled figure.

For how expense categorisation works, see Deductible expenses.