how do i calculate noi

What is NOI?

NOI (Net Operating Income) is the income a property generates after you subtract operating expenses, but before debt payments and taxes. It is one of the most important numbers in real estate investing because it tells you how the property performs on its own.

If you are asking, “how do I calculate NOI?” the short answer is:

The NOI Formula (Simple Version)

Most investors calculate it in this order:

• Start with potential gross rental income (what you would collect if fully occupied).
• Subtract vacancy and credit loss (income lost from vacancies/non-payment).
• Add other property income (parking, laundry, pet fees, storage, etc.).
• Subtract operating expenses (repairs, management, taxes, insurance, utilities paid by owner, etc.).

Step-by-Step: How to Calculate NOI

1) Calculate Gross Rental Income

This is your annual scheduled rent if all units are occupied and paying in full.

• Single-family rental: monthly rent × 12
• Multi-family: sum of all unit rents × 12
• Commercial: total contracted base rent for the year

2) Estimate Vacancy & Credit Loss

No property is occupied 100% of the time forever. Apply a realistic vacancy rate based on your market and asset type.

• Formula: Vacancy Loss = Gross Rental Income × Vacancy Rate
• Example: $120,000 gross rent × 5% = $6,000 vacancy loss

3) Add Other Income

Include recurring, property-related income beyond base rent:

• Parking fees
• Laundry income
• Storage fees
• Application/administrative fees
• Pet rent

4) Subtract Operating Expenses

Operating expenses are costs required to keep the property running.

• Property taxes
• Insurance
• Repairs and maintenance
• Property management fees
• Utilities paid by owner
• Landscaping, cleaning, admin, and reserves

What to Include vs. Exclude in NOI

Include in operating expenses

• Normal recurring costs to operate the property
• Reasonable replacement reserves (depending on your underwriting approach)

Do NOT include in NOI

• Mortgage principal and interest (debt service)
• Income taxes
• Capital expenditures (new roof, major renovation, large one-time upgrades)
• Depreciation and amortization

NOI Example

Suppose your annual property numbers are:

• Gross rental income: $150,000
• Vacancy rate: 6%
• Other income: $7,500
• Operating expenses: $52,000

Now calculate:

• Vacancy loss = $150,000 × 0.06 = $9,000
• Effective gross income = $150,000 − $9,000 + $7,500 = $148,500
• NOI = $148,500 − $52,000 = $96,500

Your annual NOI is $96,500.

Why NOI Matters

• Property valuation: Investors often value property using NOI and cap rate.
• Performance tracking: Rising NOI usually means stronger property performance.
• Loan underwriting: Lenders use NOI for DSCR analysis (ability to cover debt).
• Deal comparison: NOI helps compare different properties on a consistent basis.

How NOI Connects to Cap Rate

Once you have NOI, you can estimate cap rate:

If a property has NOI of $96,500 and value of $1,300,000:

Cap Rate = 96,500 ÷ 1,300,000 = 7.42%

Common NOI Mistakes

• Using gross rent and forgetting vacancy allowance.
• Mixing monthly income with annual expenses (or vice versa).
• Including mortgage payments in NOI.
• Underestimating repairs and management costs.
• Ignoring recurring non-rent income streams.

Quick NOI Checklist

• Are all inputs annualized?
• Did you include a realistic vacancy rate?
• Did you capture all recurring income?
• Did you include all operating expenses?
• Did you exclude debt service and taxes?

Final Takeaway

If you are trying to figure out “how do I calculate NOI,” remember this: take property income, adjust for vacancy and other income, then subtract operating expenses. Keep the calculation clean, consistent, and annual. Use the calculator above to run scenarios quickly and compare deals with confidence.