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NOI Calculation: The Number That Determines Your Loan

Net Operating Income drives everything—your loan amount, your rate, your valuation.

Definition

Net Operating Income (NOI): Total property income minus operating expenses, before debt service and capital expenditures. This is the number lenders use to determine how much they'll lend you.

What Is Net Operating Income (NOI)?

NOI is the single most important number in commercial real estate. It determines your loan amount, your property valuation, and whether your deal closes.

If you understand nothing else about multifamily finance, understand this formula:

NOI = Effective Gross Income − Operating Expenses

How Do You Calculate NOI Step by Step?

Let's break this down with a real example. Assume a 20-unit apartment building.

Step 1: Calculate Gross Potential Rent (GPR)

GPR is what you'd collect if every unit was occupied and paying full rent.

Unit TypeCountMonthly RentAnnual
1BR/1BA12$950$136,800
2BR/1BA8$1,200$115,200
GPR$252,000

Step 2: Subtract Vacancy and Credit Loss

No property runs at 100% occupancy. Lenders assume 5-7% vacancy even if your actual vacancy is lower.

Gross Potential Rent$252,000
Less: Vacancy (5%)($12,600)
Less: Concessions($3,000)
Less: Bad Debt($2,400)
Net Rental Income$234,000

Step 3: Add Other Income

Include all non-rent income: laundry, parking, pet fees, late fees, application fees.

Net Rental Income$234,000
Laundry Income$4,800
Parking Income$3,600
Late Fees$1,200
Effective Gross Income (EGI)$243,600

Step 4: Subtract Operating Expenses

Operating expenses include everything required to run the property. They do not include mortgage payments or capital improvements.

Expense CategoryAnnual Amount
Property Taxes$24,000
Insurance$8,400
Utilities (Owner Paid)$12,000
Repairs & Maintenance$15,000
Management (8%)$19,488
Landscaping$3,600
Contract Services$2,400
Administrative$1,800
Total Operating Expenses$86,688

Step 5: Calculate NOI

$243,600 (EGI) − $86,688 (Expenses) = $156,912 NOI

How Do Lenders Use NOI?

NOI feeds into two critical calculations: Debt Service Coverage Ratio (DSCR) and property valuation.

DSCR: Can You Pay the Mortgage?

DSCR = NOI ÷ Annual Debt Service

Lenders require a minimum DSCR, typically 1.20x to 1.35x. This means for every $1.00 in mortgage payments, you must generate $1.20 to $1.35 in NOI.

Using our example with a $156,912 NOI and a 1.25x DSCR requirement:

Maximum Annual Debt Service = $156,912 ÷ 1.25 = $125,530

This caps your mortgage payment at ~$10,461/month, which determines your maximum loan amount.

Property Valuation: The Cap Rate

Property Value = NOI ÷ Cap Rate

At a 7% cap rate, our example property is worth:

$156,912 ÷ 0.07 = $2,241,600

Every dollar of NOI you can prove increases your property value by $10-15, depending on the cap rate.

$10,000 in additional provable NOI = $140,000+ in additional property value (at 7% cap).

What Destroys NOI (and Your Loan)?

Income Haircuts

If the lender can't verify your income, they'll "haircut" it. Common scenarios:

  • Cash payments not deposited: You say you collected $5,000 cash. Bank shows $0. Lender credits $0.
  • Section 8 in a different account: $22,000/year hitting an affiliate account. If not documented, lender credits $0.
  • Inconsistent deposits: Rent roll shows $10,000/month. Bank shows $8,500. Lender uses $8,500.

Expense Add-Backs

If your expenses look artificially low, lenders will add standardized expenses:

  • No management fee? Lender adds 5-8% management expense, even if you self-manage.
  • No reserves? Lender adds $250-300/unit for replacement reserves.
  • Below-market taxes? Lender projects post-sale tax reassessment.

What Is the Difference Between Your NOI and Lender NOI?

Lenders don't blindly accept your NOI. They adjust it to reflect "stabilized" or "underwritten" performance:

Your T-12Lender Adjustment
3% vacancyAdjusted to 5% minimum
$0 management (self-managed)Added 6% management fee
$0 reservesAdded $250/unit reserves
Cash income (unverified)Excluded from income

The gap between your NOI and the lender's underwritten NOI is where deals get reduced—or killed.

How Do You Protect Your NOI?

  1. Deposit everything. Every rent payment, every fee, every dollar of income goes through a bank account.
  2. Document your income mix. If you have Section 8, provide the HAP contracts. If you have commercial tenants, provide the leases.
  3. Keep receipts for expenses. If you can't prove you paid it, it may not count as an expense—which sounds good until you realize unrealistically low expenses trigger add-backs.
  4. Reconcile monthly. Your T-12 should tie to bank statements within 1-2% every month.

NOI is not what you earned. It's what you can prove you earned. The difference is your loan amount.

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