Definition
Operating expenses (often shortened to OpEx) are the recurring costs required to operate and maintain an income-producing property. Operating expenses include things like taxes, insurance, utilities, repairs, payroll, and property management. They directly reduce Net Operating Income (NOI).
Where Operating Expenses Fit in the NOI Equation
In most real estate underwriting, NOI is calculated as:
- NOI = Effective Gross Income (EGI) − Operating Expenses
Because valuation often starts with NOI (for example, using a cap rate), operating expenses are one of the biggest drivers of value.
What Operating Expenses Typically Include
- Property taxes
- Property insurance
- Utilities: water/sewer, trash, gas, electric (owner-paid portions)
- Repairs & maintenance: plumbing, electrical, HVAC service, turns, minor parts and labor
- Payroll / onsite staffing: leasing, maintenance techs, managers (if applicable)
- Property management fees (third-party or an internal management allocation)
- Contract services: landscaping, snow removal, janitorial, pest control, security
- General & administrative: office, bank fees, postage, software, permits
- Marketing & leasing: advertising, ILS listings, resident events (varies by property)
- Legal / accounting (routine operating-level services)
What Operating Expenses Usually Exclude
These items are typically not included in operating expenses when calculating NOI:
- Debt service: mortgage principal and interest
- Depreciation and amortization (non-cash accounting items)
- Income taxes (entity or investor level)
- Capital expenditures (CapEx): roof replacement, major HVAC replacement, parking lot resurfacing
- Leasing commissions / tenant improvements (more common in commercial; sometimes treated below NOI)
- Owner distributions
Note: Some underwriting treats recurring “capital-like†items (for example, unit turns or appliance replacements) as CapEx reserves rather than OpEx. The key is to be consistent and not double-count.
Common Ways Expenses Are Analyzed
- Per unit per year: total OpEx ÷ number of units
- Per square foot: common for certain property types
- OpEx ratio: operating expenses ÷ effective gross income
- Fixed vs variable: which costs scale with occupancy (utilities, turnover) vs don’t (taxes)
Example
A 40-unit property has $900,000 of Effective Gross Income (after vacancy/credit loss). Annual operating expenses are $360,000.
- NOI = 900,000 − 360,000 = $540,000
- OpEx per unit = 360,000 ÷ 40 = $9,000/unit/year
- OpEx ratio = 360,000 ÷ 900,000 = 40%
If you reduce controllable expenses by $25,000 without hurting revenue, NOI increases by $25,000—which can materially increase value in a cap-rate valuation framework.
Why It Matters
- NOI and valuation: OpEx is a direct lever on NOI and therefore a direct lever on price.
- Durability: high fixed expenses (taxes/insurance) can pressure cash flow in downturns.
- Operational edge: good operators improve margins through procurement, staffing, and systems.
- Risk management: insurance and taxes can spike; underwriting should include buffers and sensitivity tests.
Common Pitfalls
- Underestimating taxes after sale: assessed value may reset, raising property taxes.
- Ignoring insurance inflation: premiums can jump materially year-to-year.
- Double counting: including an expense in OpEx and also reserving for it in CapEx.
- Using “T-12†blindly: trailing expenses may be artificially low (deferred maintenance) or high (one-time events).
- Not separating controllable vs uncontrollable: it’s easier to improve repairs, payroll, contracts than taxes.