Two Different Questions

NOI and cash flow answer different questions about the same property.

NOI answers: How much money does this property generate from operations, independent of who owns it or how it is financed?

Cash flow answers: How much actual money lands in my bank account each year after paying everything including the mortgage?

Both numbers matter. They are not the same number. Mixing them up causes investors to overpay, mis-underwrite refinances, and misread their actual returns.

NOI - The Property Number

NOI equals effective gross income minus operating expenses.

Effective gross income:

  • Gross scheduled rent at full occupancy
  • Minus vacancy losses
  • Plus other income (laundry, parking, late fees, RUBS)

Operating expenses:

  • Property taxes
  • Insurance
  • Property management fees
  • Repairs and maintenance
  • Utilities (landlord-paid)
  • Landscaping and common-area maintenance
  • Advertising and leasing costs
  • Professional services (legal, accounting)
  • Capital reserves (sometimes included, sometimes not)

NOI is calculated before debt service, depreciation, or income taxes. It does not change based on how you financed the property. It does not change based on your tax situation. It is purely operational.

Why this matters: When you sell or refinance a property, the appraiser calculates NOI to determine value. NOI is the language of commercial real estate valuation. Cap rate times NOI equals value.

Cash Flow - The Owner Number

Cash flow equals NOI minus debt service minus capital expenditures.

Debt service:

  • Principal and interest payments on any loan
  • Includes both bank loans and seller-financed notes

Capital expenditures:

  • Roof replacements, HVAC, structural work
  • Items not in the operating expense line
  • Often funded from cash flow or reserves

The result is what actually hits your bank account.

Why this matters: When you decide whether a deal is good for you personally, cash flow matters. NOI of $90,000 sounds great until you realize you have $84,000 in debt service. Your actual cash flow is $6,000, not $90,000.

A Worked Example

Property: 12-unit acquired with seller financing.

Income:

  • Gross scheduled rent: $144,000
  • Vacancy loss (7 percent): -$10,080
  • Other income: $3,600
  • **Effective gross income: $137,520**

Operating expenses:

  • Taxes: $9,800
  • Insurance: $4,200
  • Management (8 percent of collected): $9,632
  • Repairs and maintenance: $7,200
  • Utilities (landlord water and trash): $3,600
  • Landscaping and snow: $2,400
  • Professional services: $1,200
  • **Total operating expenses: $38,032**

NOI = $137,520 minus $38,032 = $99,488

Below the line:

  • Seller note debt service: $39,600 ($3,300/month)
  • Bank loan debt service: $0 (no bank loan)
  • Capital expenditure reserves: $3,600 ($300/unit)

Annual cash flow = $99,488 minus $39,600 minus $3,600 = $56,288

The property generates $99,488 of NOI. The owner takes home $56,288 of cash flow. Both numbers are correct. They answer different questions.

When You Need NOI

  • **Valuing a property at purchase:** Value equals NOI divided by cap rate.
  • **Refinancing:** Lenders calculate NOI to size your loan.
  • **Comparing properties:** Two properties with different debt structures should be compared on NOI, not cash flow.
  • **Reporting to investors:** Property-level NOI is the standard metric.

When You Need Cash Flow

  • **Personal investment decisions:** Will this deal feed my family?
  • **Underwriting return metrics:** Cash-on-cash return uses cash flow, not NOI.
  • **Tax planning:** Cash flow drives your tax position (after depreciation adjustments).
  • **Reserve planning:** How much can you save monthly for capex and future down payments?

Common Mistakes

Confusing NOI for cash flow: A seller pitches a property with $90,000 NOI. You assume that is what you take home. You forget the $70,000 in debt service. Your actual cash flow is $20,000.

Confusing cash flow for NOI when refinancing: You tell the lender the property "cash flows $15,000 per month." The lender wants NOI, which is $25,000 per month before your debt service. Provide the right number.

Not separating debt by source: A property with a $300,000 bank mortgage and a $200,000 seller note has $500,000 of debt. The debt service is split across two payments. Track each separately so you know what to refinance when.

Underwriting cash flow without capital reserves: If you ignore capex, your cash flow looks great until the roof needs replacing. Always reserve $200 to $400 per unit per year.

The Net Operating Number Variants

You may also encounter these:

  • **EGI (Effective Gross Income):** Before operating expenses.
  • **EBITDA:** In real estate context, similar to NOI but may include some items NOI excludes.
  • **Cash on cash return:** Cash flow divided by total cash invested.
  • **IRR:** Full-cycle return including cash flow and appreciation, time-weighted.

NOI and cash flow are the two foundational numbers. The others build from them.

Practical Takeaway

When evaluating a deal:

  1. Calculate NOI first. This determines what the property is worth and what it can support in debt.
  2. Then layer in debt service to get cash flow. This tells you what you actually take home.
  3. Compare both to your acquisition price. NOI divided by price equals your acquisition cap rate. Cash flow divided by cash invested equals your cash-on-cash return.

If either number disappoints, the deal does not work. Both must support the investment for it to make sense.