NOI Calculator — Net Operating Income Made Simple

What Is Net Operating Income (NOI)?

Net Operating Income (NOI) is the total income a property generates after subtracting all operating expenses — but before accounting for mortgage payments, capital expenditures, or income taxes. It is the single most important number in commercial and residential real estate analysis because it measures a property's ability to generate profit from operations alone, independent of how the deal is financed.

Effective Gross Income is your gross rental income minus vacancy and credit losses. If a property collects $36,000 per year in rent and has a 5% vacancy rate, the EGI is $36,000 − $1,800 = $34,200.

NOI matters because it feeds directly into other critical metrics. Cap rate is NOI divided by property value. DSCR is NOI divided by annual debt service. Lenders, appraisers, and investors all start with NOI when evaluating a deal. If you get NOI wrong, every downstream calculation is wrong too.

How to Calculate NOI — Step by Step

Let's walk through a concrete example using a single-family rental property that rents for $3,000 per month.

Step 1 — Calculate Gross Annual Rent. Multiply the monthly rent by 12. $3,000 × 12 = $36,000 gross annual rent.

Step 2 — Subtract Vacancy Loss. Assume a 5% vacancy rate. $36,000 × 0.05 = $1,800 vacancy loss. Effective Gross Income = $36,000 − $1,800 = $34,200.

Step 3 — Add Up Operating Expenses. Include property taxes ($3,600), insurance ($1,800), maintenance and repairs ($3,600), property management ($0 if self-managed), and any other recurring costs. Total operating expenses = $9,000.

Step 4 — Subtract Expenses from EGI. NOI = $34,200 − $9,000 = $25,200 per year, or $2,100 per month.

Remember: do not include your mortgage payment, capital improvements (like a new roof), or income taxes. NOI is strictly about operating performance.

What Is a Good NOI?

Unlike cap rate or cash-on-cash return, NOI is a dollar amount — not a percentage — so there is no universal "good" number. Whether your NOI is strong depends on the property's value, your market, and your investment goals. Here are the key ways to interpret NOI:

• NOI relative to property value (cap rate). A $25,200 NOI on a $300,000 property gives an 8.4% cap rate — strong in most markets. The same NOI on a $600,000 property gives only 4.2% — acceptable in prime urban areas but thin elsewhere.
• NOI relative to debt service (DSCR). If your annual mortgage payments are $18,000, your DSCR is $25,200 / $18,000 = 1.40. Most lenders require a minimum DSCR of 1.20 to 1.25, so 1.40 provides a healthy cushion.
• NOI per unit. For multi-family properties, NOI per unit allows apples-to-apples comparison. A 4-unit building with $40,000 NOI ($10,000/unit) is more efficient than an 8-unit building with $56,000 NOI ($7,000/unit).
• Operating expense ratio (OER). A healthy OER for residential rentals is typically 35% to 45%. If your OER exceeds 50%, your expenses may be eating too much of your income.

The most practical test: does the NOI comfortably cover your debt service and still leave cash flow? If yes, the NOI is working for you. Use our DSCR calculator to check that ratio directly.

NOI vs Cash Flow — What's the Difference?

NOI and cash flow are closely related, but they are not the same thing. The critical difference is that NOI excludes debt service (your mortgage payment), while cash flow includes it.

A property can have a strong, positive NOI but produce negative cash flow if the mortgage payment is large enough. Conversely, a property purchased all-cash has zero debt service, so its cash flow equals its NOI. This is exactly why NOI is used for comparing properties — it strips out the financing variable and shows you the property's intrinsic earning power.

To see how NOI translates into actual cash flow under your specific financing terms, use our full rental property calculator, which models mortgage payments, cash-on-cash return, and 5-year projections.

How to Improve Your Property's NOI

Improving NOI comes down to two levers: increase income or reduce expenses. Here are five proven strategies experienced investors use:

• Raise rents to market rate. Many landlords under-price long-term tenants. Research comparable rents in your submarket and implement gradual increases. Even a $50/month increase adds $600/year to NOI per unit.
• Reduce vacancy. Every month a unit sits empty costs you one month of rent. Improve your marketing, respond to inquiries faster, offer competitive move-in incentives, and keep good tenants happy. Reducing vacancy from 8% to 4% on a $36,000 gross rent property adds $1,440 to NOI.
• Add ancillary income streams. Charge for covered parking, storage units, pet rent, laundry, or vending. These small revenue lines compound across units and directly increase NOI without increasing the property's rent.
• Shop insurance and property tax appeals. Insurance premiums can vary significantly between carriers. Get quotes annually. Property tax assessments can often be challenged — many investors save thousands by filing an appeal with comparable sales data.
• Implement preventive maintenance. Reactive repairs are always more expensive than proactive ones. A structured maintenance schedule reduces emergency calls, extends the life of building systems, and keeps your maintenance line item predictable and lower over time.

Frequently Asked Questions