Multifamily Operating Expenses: What Every Line Item Should Cost Per Door (2025 Benchmarks)

Your multifamily portfolio generated $1.4 million in gross rents last year. After operating expenses, net operating income came in at $620,000 (a 56% operating expense ratio).

Is that good? Bad? You are not sure. You have a sense that other operators are running tighter, but you do not have the data to benchmark against, and your books do not give you per-door expense visibility by category. You know the total. You do not know which line items are running hot or why.

This is the operating expense visibility problem that most multifamily operators share. The aggregate number is available. The diagnostic detail is not. And without the detail, the aggregate is nearly useless for decision-making: it tells you that costs are high but not where the leak is. The guide to per-door profitability analysis covers how to structure this reporting so that category-level expense data surfaces in monthly statements rather than in year-end totals.

What follows is the benchmark framework that expert-led, AI-powered multifamily accounting produces: operating expenses by category, benchmarked against 2025 market data, with the per-door figures that tell you whether each line is in range or needs attention. The numbers come from NMHC data, NAA Survey of Operating Income and Expenses, and the operating patterns Numetix observes across multifamily portfolios in its managed accounting work.

How to read multifamily operating expenses: Three metrics you need

Before the benchmarks, the framework. Multifamily operating expenses can be expressed three ways, and each serves a different analytical purpose.

Operating expense ratio (OER) expresses total operating expenses as a percentage of gross potential rent (GPR). This is the most commonly referenced benchmark in institutional multifamily analysis. A 40% OER means that for every dollar of rent you could theoretically collect from fully occupied units, 40 cents goes to operating the property before debt service. Industry benchmarks for well-managed Class B suburban multifamily typically run 35% to 45%. Class A urban properties run higher (40% to 50%) because of higher insurance, amenity costs, and staff ratios. Class C value-add properties can run 50% to 60% or higher during renovation cycles.

Per-door annual operating expense expresses the same number divided by unit count. This is more useful for operational management than OER because it is scale-neutral and directly comparable across properties of different sizes.

Per-door expense by category is where actual diagnosis happens. Knowing that total per-door expense is $6,200 tells you nothing about where the cost lives. Knowing that maintenance is running $1,600 per door and the benchmark for your property class is $900 tells you exactly where to look. This is the number most multifamily operators cannot produce on demand.

The rest of this article works through the five primary expense categories with 2025 benchmarks for each. If you cannot produce per-door category data from your current accounting setup, that is itself a finding.

Category 1: Maintenance and repairs ($800 to $1,800 per door)

Maintenance is the most variable expense category in multifamily, and the hardest to benchmark meaningfully across an entire industry. The range is wide for a reason: it is driven primarily by three factors that vary significantly across portfolios.

Property age. A 1970s garden-style complex in a secondary market will run materially higher maintenance costs than a 2015 construction in the same market. Plumbing, HVAC systems, roofing, and electrical panels degrade on predictable schedules, and older properties are further along those schedules.

Deferred maintenance history. A property managed conservatively (with routine preventive maintenance, documented HVAC service contracts, regular roof inspections) will run lower annual maintenance costs than a property where maintenance was deferred to preserve short-term cash flow. A $3,000 HVAC repair that was preventable with a $300 annual service contract is an extreme example, but the pattern repeats across every major system.

Turn costs. Maintenance during tenant turnover (painting, carpet, appliance repair, deep cleaning) varies directly with turnover rate. A portfolio with a 25% annual turnover rate will run higher per-unit maintenance costs than one with 15% turnover, even if per-turn costs are identical.

The 2025 benchmark for Class B suburban multifamily, 10 to 25 years old, with competent preventive maintenance programs: $900 to $1,200 per door annually. Class A newer construction: $700 to $950. Value-add or older Class C properties in active renovation cycles: $1,500 to $2,000 or higher during renovation years, settling to $1,100 to $1,400 post-stabilization. For how to structure the expense capture that makes these benchmarks actionable month to month, the guide to maintenance expense tracking covers the workflow and accounting setup that produces category-level maintenance data automatically.

If you are running above the high end of your class benchmark, the first diagnostic question is whether the expense is accurately classified. A $6,000 HVAC replacement that should be capitalized and depreciated is often coded as maintenance expense, inflating the maintenance line and understating NOI.

Category 2: Property management fees (8% to 12% of collected revenue)

Management fees are the most misread expense category in multifamily, because the stated fee and the actual all-in cost of management are almost never the same number.

A management contract that says 10% of collected revenue looks simple. In practice, it is accompanied by a fee schedule that includes leasing fees (typically 50% to 100% of one month's rent per new lease), lease renewal fees ($100 to $300 per renewal), maintenance coordination fees (6% to 10% markup on third-party invoices), eviction coordination fees ($150 to $400 per proceeding), and in some cases, inspection fees, reserve management fees, and vacancy reporting fees.

The unbundled all-in cost of management for a portfolio with 25% annual turnover, normal maintenance activity, and typical renewal rates typically runs 15% to 22% of collected revenue when all line items are included. This is not a complaint about management companies: it reflects the genuine labor cost of professional property management. It is a warning that the 10% base fee understates what you are actually paying by 50% to 100%.

The 2025 per-door benchmark for management fees (base fee only): $18 to $28 per unit per month, or approximately $220 to $340 per door annually. Including full leasing and ancillary costs: $350 to $550 per door annually in most markets.

Category 3: Property insurance ($400 to $700 per unit annually)

Property insurance for multifamily has seen significant cost increases since 2022, driven by catastrophic loss events, reinsurance market tightening, and construction cost inflation that increased replacement cost valuations. In coastal markets, hurricane or flood exposure zones, and wildfire-adjacent areas of the western US, premiums have increased materially since 2021.

The 2025 benchmark for multifamily property insurance in inland, non-coastal markets: $400 to $550 per unit annually. Coastal or high-risk markets: $600 to $900 or higher. Properties with favorable loss histories, masonry construction, and recent roof replacements sit at the lower end.

Operators who go to market annually (even if they ultimately stay with the same carrier) capture meaningfully lower premiums on average over a three-year period than those who simply accept what the incumbent broker quotes at renewal.

Category 4: Property taxes (15% to 35% of effective gross income)

Property taxes are the expense category with the widest variation and the least operator control in the short run. A property in Houston might pay 2.5% of assessed value annually. A similar property in Memphis might pay 1.1%. The range in tax burden as a percentage of effective gross income runs from 12% in low-tax markets to 35% in high-tax markets.

Benchmarking property taxes is only meaningful within a market. What is benchmarkable and controllable is the appeal process. Success rates for well-documented multifamily tax appeals typically produce reductions of 10% to 25% of the assessment. Operators who file appeals systematically on every property every year capture meaningful savings per unit annually in markets where the economics support it.

The accounting implication: your property tax accrual should be updated each year to reflect the actual tax bill or the appealed assessment, not simply carried forward from the prior year. Carrying forward prior-year tax expense on a growing portfolio produces materially wrong NOI calculations.

Category 5: Administrative and accounting ($200 to $450 per door annually)

Administrative expenses in multifamily include software (property management platform, accounting software, document management), accounting services (bookkeeping, financial statement preparation, tax compliance), payroll if the management function is internalized, office overhead allocated to the portfolio, and professional services (legal, compliance, licensing).

The benchmark for this category in portfolios of 50 to 200 doors: $200 to $350 per door annually. The drivers of the high end are internalized management with dedicated administrative staff, multi-state operations that increase compliance costs, and portfolios with complex entity structures that require more accounting infrastructure. The account structure that makes this category trackable separately from management fees is covered in the guide to chart of accounts for property management.

This is the expense category where most multifamily operators are systematically underreporting. Administrative and accounting expenses are often partially absorbed into the owner's personal compensation or the management company's overhead. When the portfolio is eventually sold, acquirers discover that the administrative cost line in the historical financials was 30% to 50% below the real cost of running the operation.

The accounting-specific component (bookkeeping, monthly close, financial statement preparation, tax compliance, and per-entity reporting) typically runs $3 to $6 per door per month for a professionally managed outsourced accounting service.

The OER above 50%: What it almost always means

An operating expense ratio above 50% in a stabilized multifamily portfolio almost always traces to one of three sources, and the order of investigation matters.

First, check for misclassification. Capital expenditures coded as operating expenses (HVAC replacements, roof work, major appliance replacements) inflate the operating expense line and depress NOI without reflecting actual operating performance. A qualified accountant reviewing the maintenance and repair line for capital items will typically find $400 to $1,200 per door in misclassified capital expenditures in portfolios where this review has never been done.

Second, check for vacancy loss mishandling. Vacancy loss (the revenue lost to unoccupied units) is sometimes coded as an operating expense rather than as a revenue reduction. If your books show a gross revenue line that includes potential rents from vacant units and then a separate vacancy loss expense line to reverse them, this is double-counting the vacancy impact. Vacancy is a revenue problem, not an expense problem.

Third, if classification is clean, you have a genuine cost problem. The four categories most likely to drive a high OER are maintenance (deferred maintenance catching up), management fees (full unbundled cost higher than realized), insurance (market-driven increases since 2022), and property taxes (assessment not appealed or recently reassessed at a higher rate post-acquisition). For how these categories integrate into a budget and planning framework, the guide to multifamily budgeting across 200 doors covers how to set category-level targets and track against them monthly.

The diagnostic process requires per-door category data, which requires bookkeeping structured to produce it. A single income statement showing "operating expenses: $640,000" for a 100-unit portfolio tells you the OER is 51%. It does not tell you where the 51% is living or which category is responsible for the four points above the 47% benchmark you are targeting. Understanding the relationship between OER and cash runway is critical for portfolios where a high OER is compressing the cash available to fund capital reserves or service debt.

This is the accounting infrastructure problem that underlies most multifamily expense management discussions. The data to manage costs more precisely exists in the transactions. The question is whether the bookkeeping system is structured to surface it, or whether it aggregates expenses into categories too broad to be actionable.

Frequently asked questions

How do you calculate operating expense ratio (OER) for a multifamily property?

OER = Total Operating Expenses divided by Gross Potential Rent. Total operating expenses include all five categories in this guide (maintenance, management fees, insurance, property taxes, and admin) but exclude debt service and capital expenditures. Gross potential rent is the theoretical maximum rent you would collect if every unit were occupied and paying market rent. Divide the first by the second and multiply by 100. A 40% OER means operating costs consume 40 cents of every potential rent dollar before debt service. If total operating expenses are $480,000 and GPR is $1.2 million, the OER is 40%.

What is the difference between gross potential rent and effective gross income in multifamily?

Gross potential rent (GPR) is the theoretical maximum: every unit occupied and paying the scheduled market rent. Effective gross income (EGI) is the more realistic figure: GPR minus vacancy loss and credit loss (uncollectable rents). If a property has 100 units at $1,200 per month, GPR is $1.44 million. At 8% vacancy, EGI is approximately $1.32 million. OER benchmarks are typically expressed as a percentage of GPR. Property taxes are often benchmarked as a percentage of EGI. When comparing your OER against industry data, confirm which denominator the source uses, because the same portfolio can appear to have a 40% OER (GPR denominator) or a 43% OER (EGI denominator) without any underlying cost difference.

How often should a multifamily portfolio owner review per-door expense data by category?

Monthly at the OER level: compare the current month's ratio to the prior month and to the target range for your property class. This review takes 15 minutes and catches meaningful shifts in total cost before they compound. Quarterly at the per-door category level: benchmark each of the five categories (maintenance, management fees, insurance, property taxes, and admin) against the class-appropriate ranges in this guide and flag any category that has moved more than one percentage point from the prior quarter. Annually as part of the budget cycle: use the prior year's per-door category data to set next year's targets by category, trigger vendor renegotiations where costs have drifted, and update property tax accruals to reflect the actual or appealed assessment. Operators who review only at year-end consistently discover cost problems that have been compounding for six to ten months.