Almost every number you’ll hear in a commercial real estate deal traces back to one figure. Cap rate uses it. Valuation depends on it. Loan sizing leans on it. That figure is net operating income.
If you’re evaluating a property in PA, NJ, or DE, understanding what net operating income is — and what it deliberately excludes — is the foundation everything else sits on. Let’s break it down.
What Is Net Operating Income?
Net operating income (NOI) is a property’s total income minus its operating expenses, before mortgage payments, capital improvements, and income taxes.
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Think of NOI as the property’s own earning power, stripped of how it’s financed or owned. Two investors could buy the same building with completely different loans, but the NOI stays the same. That’s what makes it such a useful, comparable number.
How to Calculate NOI
The math is simple; the discipline is in what you include. Start with all income, subtract all operating expenses:
- Gross potential income — total rent if the property were fully leased.
- Minus vacancy and credit loss — a realistic allowance for empty space and unpaid rent.
- Plus other income — parking, laundry, signage, reimbursements.
- Minus operating expenses — taxes, insurance, maintenance, management, utilities, and repairs.
What’s left is your NOI. A building with $300,000 in effective income and $110,000 in operating expenses has an NOI of $190,000.
What NOI Leaves Out — and Why
Here’s where people make mistakes. Several big costs are deliberately excluded from NOI, and if you sneak them in, your number stops being comparable to anyone else’s.
- Mortgage payments (debt service) — excluded because financing varies by owner.
- Capital expenditures — a new roof or HVAC system is a capital item, not an operating expense.
- Income taxes — these depend on the owner’s tax situation, not the property.
- Depreciation — an accounting entry, not a cash cost.
Leaving these out is the point. NOI measures the asset, not the owner. Once you layer financing and taxes back in, you move from NOI toward actual cash flow — a different, owner-specific number.
NOI vs Cash Flow
| Figure | Includes Financing? | What It Measures |
|---|---|---|
| NOI | No | The property’s own earning power |
| Cash Flow | Yes (after debt service) | What lands in the owner’s pocket |
NOI is what you use to value the property and compare deals. Cash flow is what you use to see what you personally take home after the mortgage. Both matter — they just answer different questions.
Why NOI Is Where We Start
When we underwrite a property with a client, NOI is the first thing we pressure-test. Is the vacancy allowance realistic? Are expenses complete, or is something being left off to make the number look better? A too-clean NOI is often a warning sign.
Get the NOI right and the cap rate, valuation, and loan math all fall into place. Get it wrong, and every number downstream is off. That’s why it’s worth slowing down on this one.
Frequently Asked Questions About NOI
What is net operating income in real estate?
Net operating income is a property’s total income minus its operating expenses, calculated before mortgage payments, capital improvements, and income taxes. It measures the property’s own earning power independent of how it’s financed.
How do you calculate NOI?
Take gross potential income, subtract vacancy and credit loss, add other income, then subtract operating expenses like taxes, insurance, maintenance, and management. The result is the net operating income.
Does NOI include the mortgage?
No. NOI excludes mortgage payments because financing varies from owner to owner. Subtracting debt service from NOI gives you cash flow, which is an owner-specific figure.
What’s the difference between NOI and cash flow?
NOI measures the property’s earning power before financing, while cash flow is what remains after mortgage payments. NOI is used for valuation and comparison; cash flow shows what the owner actually takes home.
Why is NOI important?
NOI drives cap rate, property valuation, and how much a lender will lend. Because it excludes owner-specific costs, it lets investors compare properties on equal footing, which is why it’s the foundation of most CRE analysis.
Considering Your Next Commercial Investment?
SCG works with investors across asset classes — multifamily, mixed-use, retail, industrial, office — throughout PA, NJ, and DE. We can help you pressure-test the NOI, run the numbers, and move on the right deal.
Call us at 215.995.0191 or reach out through our contact page to start an investor conversation.
